Below are the 3 main physical attackers I feel that justify Alomomola having 232 HP / 252 Def / 32 SpAtk. I know there are other cases where the difference matters besides the ones listed below but I am drawing a blank.
Most stall teams have relatively little for Choice Banded Heracross. If Alomomola lacks HP investment it no longer has an effective chance to deal with Heracross by PP stalling Close Combat.
252 Atk Choice Band Heracross Close Combat vs. 232 HP / 252+ Def Alomomola: 237-280 (44.8 - 52.9%) -- guaranteed 3HKO after Leftovers recovery
252 Atk Choice Band Heracross Close Combat vs. 40 HP / 252+ Def Alomomola: 237-280 (49.2 - 58.2%) -- 64.5% chance to 2HKO after Leftovers recovery
252 Atk Choice Band Heracross Close Combat vs. 232 HP / 252+ Def Alomomola: 237-280 (44.8 - 52.9%) -- 28.9% chance to 2HKO (Chance of living after SR and Protect assuming still has lefties)
252 Atk Choice Band Heracross Close Combat vs. 40 HP / 252+ Def Alomomola: 237-280 (49.2 - 58.2%) -- 97.7% chance to 2HKO (Chance of living after SR and Protect assuming still has lefties)
Another trouble Pokemon for Stall is SD Gatr. With HP investment, Alomomola can reliably beat Gatr's without substitute. The difference between the two sets is that the HP investment allows Alomomola to do the following safely: to come in on the SD>Toxic after Crunch>Wish on SD/Crunch with no chance of dying outside a critical hit. 40 HP investment has to essentially be at 100% without SR to stand a chance at doing this or rely on prediction after the Toxic (will he SD or Crunch). In addition to this, 232 HP Alomomola can also deal with Adamant Gatr with a decent chance while 40 HP has no chance at all.
+2 252 Atk Life Orb Sheer Force Feraligatr Crunch vs. 232 HP / 252+ Def Alomomola: 212-250 (40 - 47.2%) -- guaranteed 3HKO after Leftovers recovery
+2 252 Atk Life Orb Sheer Force Feraligatr Crunch vs. 40 HP / 252+ Def Alomomola: 212-250 (44 - 51.9%) -- guaranteed 3HKO after Leftovers recovery
+2 252 Atk Life Orb Sheer Force Feraligatr Crunch vs. 232 HP / 252+ Def Alomomola: 212-250 (40 - 47.2%) -- 1.2% chance to 2HKO after Stealth Rock and Leftovers recovery
+2 252 Atk Life Orb Sheer Force Feraligatr Crunch vs. 40 HP / 252+ Def Alomomola: 212-250 (44 - 51.9%) -- 71.9% chance to 2HKO after Stealth Rock and Leftovers recovery
For when Alomomola comes into a +2 Gatr Crunch.
+2 252 Atk Life Orb Feraligatr Earthquake vs. 232 HP / 252+ Def Alomomola: 203-239 (38.3 - 45.1%) -- guaranteed 3HKO (Chance after SR+Protect)
+2 252 Atk Life Orb Sheer Force Feraligatr Crunch vs. 40 HP / 252+ Def Alomomola: 212-250 (44 - 51.9%) -- 14.1% chance to 2HKO (Chance after SR+Protect)
Finally Mega Beedrill. Without HP investment, U-turn chips away at Alomomola's health at a rate that exceeds it's passive recovery. This allows it to be able to 2HKO Alomomola reliably with Poison Jab after just a few U-Turns on the 40 HP set after Knock Off. In fact, Beedrill can deal with 40 HP Alomomola after having Alomomola come in twice on Beedrill if certain conditions are met.
Edit: The reasoning behind why you would want to use Alomomola for a Beedrill is two fold. Alomomola lets you Protect on the commonly paired Rotom to scout for Trick and can also passively wear Rotom down through status damage forcing Beedrill to switch to something else. The other reason is that Alomomola is relatively unaffected from a loss of Leftovers compared to other walls due to the passive recovery of Regenerate.
252+ Atk Adaptability Mega Beedrill U-turn vs. 232 HP / 252+ Def Alomomola: 156-184 (29.4 - 34.7%) -- 100% chance to 4HKO after Leftovers recovery
252+ Atk Adaptability Mega Beedrill U-turn vs. 40 HP / 252+ Def Alomomola: 156-184 (32.4 - 38.2%) -- 1.4% chance to 3HKO after Leftovers recovery
252+ Atk Adaptability Mega Beedrill Poison Jab vs. 232 HP / 252+ Def Alomomola: 178-210 (33.6 - 39.6%) -- 22.3% chance to 2HKO after Stealth Rock and poison damage
252+ Atk Adaptability Mega Beedrill Poison Jab vs. 40 HP / 252+ Def Alomomola: 178-210 (37 - 43.6%) -- 97.7% chance to 2HKO after Stealth Rock and poison damage
Now for the special investment difference. Alomomola doesn't have that much problems taking neutral special hits naturally. Alomomola can still effective wish pass against Florges with a potential loss of no health after leftovers (at most loses ~5.25% after Regen). Also worth mentioning, Florges can't even force Alomomola out while Alomomola can force Florges out by Toxic'ing and wasting Aromatherapy PP. Since Florges pretty much has the highest special attack out of any walls, this means that no other neutral STAB attack really matters to Alomomola from any other walls. And again, Alomomola can tank a dark pulse from modest Mega Blastoise, Toxic back, Protect once and switch out and only lose at most a total of 12.9% without a critical hit. That is an effective base 120 power move from a base +135 special attack. What more does Alomomola need? In addition to this, Alomomola is almost always paired with a special defensive Pokemon. According to the current
uu-1630.txt, Alomomola is paired with Blissey a whopping 31.3% of the time and the rest of the list is riddled with special walls.
I feel these above reasons alone justify the 232/252/24 EV spread being mentioned at least in the OO section. Personally I feel the analysis should feature both EV sets in the Sunfish set with the lower HP variant coming first while the set details discusses that 40/252/216 is more for a utility wall on balance and 232/252/24 is more for hard physical wall for full stall.
Edit: In case you were wanting the exact difference between physical and special bulks, they are as follows. 232 HP Alomomola takes 91% of the physical damage compared to 40 HP Alomomola. 40 HP Alomomola conversely takes 81% of the special damage 232 HP Alomomola would take. In addition to this, 232 HP Alomomola has a higher effective HP due to 232 HP Alomomola receiving the following: 3 extra HP from each leftovers tick, Wish healing for 24 more HP, and Regenerator healing for 16 extra HP. After two Leftover ticks and switching, 232 HP Alomomola would have healed for 22 HP more than 40 HP Alomomola! Even if you Include SR into that (6 extra HP damage), Alomomola still comes away with 16 HP extra. With so many sources of passive % HP healing, Health scales much more into Alomomola's effective bulk than apparent at first.
In addition to this, I remembered another case where the difference in HP matters. Hone Claws Aerodactyl, +1 Stone Edge is always a 3HKO on 232 HP Alomomola after SR while it has a 64.5% chance to 2HKO 40 HP Alomomola.
+1 252 Atk Mega Aerodactyl Stone Edge vs. 232 HP / 252+ Def Alomomola: 210-247 (39.6 - 46.6%) -- guaranteed 3HKO after Stealth Rock and Leftovers recovery
+1 252 Atk Mega Aerodactyl Stone Edge vs. 40 HP / 252+ Def Alomomola: 210-247 (43.6 - 51.3%) -- 64.5% chance to 2HKO after Stealth Rock and Leftovers recovery
Crobat: Super Fang needs added to OO. Hits steels it would otherwise come in free (Mega Aggron/Empoleon) and does significant damage to walls.