Thanks for the answers
SLDR and
ironwater, to keep a long reply short:
I am well aware aware of the practical differences, in that trapping moves require a turn, whereas trapping abilities are automatic, along with how as SLDR said, certain useful status moves such as Taunt, Encore and Trick would be more difficult to pull off on a target with raised evasion over a target with raised defenses. I'm excluding Toxic, on the basis that Toxic from Poison types ignores evasiveness.
If it's about counterplay, you could equally Roar out or Haze both types of stat boosts, with a small but notable difference in the possibility of using Guard Swap versus the impossibility of using Heart Swap
Sure enough, the combination of a trapping move and an accuracy lowering move, Block and Mud Slap, is more often than not a liability, but I don't view this as a question of practice, rather of principle. I don't think usage, which is to say rarity, is determining or success therein, as these are grounds for the removal of OHKO Clause, which were discussed at length during the Diamond and Pearl era.
Ultimately, my question is, both Double Team and Mud Slap serve no purpose as anything but accuracy checks (unlike Acupressure), so ought they not equally in principle be discouraged and banned?