The point of sash on this set is to extend Kartana's playtime, since it gets one-shot due to its low SpDef. If I wanted to use Life Orb, I wouldn't post this. :/
If you're using it as an attacking lead that's gonna get 2-shot/left at 1 hp at the outset of the match while dealing with an offensive piece of the opponent's, that's not extending its playtime. That's relying on surprise tactics (which work well, don't get me wrong) to remove a piece of the opponent's that you may or may not have been able to wall. For example, you can easily catch Pheromosa with this strat. They Close Combat as you click Smart Strike and that's a huge threat gone... or they just clicked U-turn anticipating your switch and then easily go into a mon like Landorus-T, Corviknight, or Moltres and wall you, while you've also lost your sash and have very little offensive power as you don't have SD + Giga Impact to threaten something else down the line.
I don't spend all battle playing around. What part of "Attacking Lead" gives you the idea of "playing around?" Does Hail even break its sash if its being regenerated by Grassy Terrain? And once again, the point of this set isn't Life Orb. Otherwise, I would've been playing LO Kartana and not even minding posting this on Smogon.
Hail doesn't break sash, but if your sash has been activated then I'm pretty sure you die to hail before you are recovered by Grassy Terrain. Niche scenario, still worth mentioning. Also, there is a point in mentioning LO, because if you are using this offensive sash lead set, then you can't also use the SD LO Giga Impact set. It's an opportunity cost.
How do you even know it walls the rest of my team? You're making assumptions of my team based on one pokemon and acting like its a valid point.
That was an example. It very well could've been removing Moltres for Pheromosa, or Mandibuzz for Spectrier, or any other defensive mon for any offensive mon that profits off their disappearance. If you build your team using a SD LO Giga Impact kart, you can exploit its forced trade capabilities. Of course, don't use SD LO Giga Impact Kart if you have a team full of stall mons or something, but in this case you probably wouldn't be using Kart in the first place. It's like using Screens Regieleki or Mega Sableye; they are incredibly good on the playstyles they fit in, but they are very bad elsewhere.
Different sets have different purposes, but trying to actively downplay one, because it doesn't suit a specific purpose, but does serve a purpose that another one doesn't server is kinda cruel, ngl.
yea but the thing is this set really doesn't have too big of a niche. It's role on teams (from what I understand) is lead off and surprise people with sash (which may not always work) and just kinda deal damage. However: 1. Kart can't deal enough wallbreaking damage without a boosting item or move, so against any team with any sort of defensive backbone, it's gonna flop and it's only gonna be able to knock off stuff. and 2. Lots of people on balanced or offensive teams like to lead off with a Scarfed mon with a pivot move, and if that's the case all the opponent has to do is click U-turn and this strategy's usefulness is removed.
The fact that this Kart can't break means that its consistent usefulness would be limited to against offensive teams. However, Kartana loses/gives up progress to many common leads on hyper offense, such as screens Regieleki (eleki sets up reflect turn 1 and lives a leaf blade, and can either die after setting up screens or volt switch out into Magearna or Moltres-G or Garchomp or another screens sweeper) and Landorus-T (after intimidate Kartana can't 2HKO landorus, and Scarf Lando EQ 2HKOs back, and if they're lead Lando they can set up rocks then boom or something). So if it can't beat HO, and it can't beat teams with a defensive core, all it can really do is lead turn 1 and hope that the opponent goes for the kill instead of clicking U-turn, or switching out into a defensive piece, or setting up hazards/screens/trick room that will benefit it's team in the long run.
I'm not saying Focus Sash Kartana is unusable. Kartana without a boosting item can still hit decently hard against offensive mons, and the threat of SD LO Giga Impact may have the opponent making choke plays. We here in the metagame discussion thread can't make you use something or not; all we can tell you is that if your goal is strictly and only to build good teams and win matches, in our collective opinion that set is not the way to do it.