>>16522656It's actually far more useful on mons with only one useful ability and a terrible other.
Ex. Shellder
Shell Armor Shellder is near worthless (even defensive ones want to keep Icicle Spear/Rock Blast), but when you breed or catch wild mons (shiny, perhaps), you will get Shellders with Shell Armor that you want to use otherwise. By using Ability Capsule, you can save it from being worthless/release fodder, and making it the very desirable Skill Link Shellder.
Its best use is to fix mistakes of RNG assigning the 'wrong' ability slot to otherwise good mons.
It's a very costly item, however, so simply switching abilities between two good ones for 'mind games' against a friend isn't an efficient use of the item.
However, you can do so if you wish.
Ex. You have a Kingdra you use against a friend. Currently, you're running the 100% Crit Sniper build.
You can use an Ability Capsule to switch it over into a Swift Swim Kingdra if your friend decides to run Shell Armor/Battle Armor mons to counter your Kingdra, allowing you to keep the same mon for battles, simply switching moves and ability.
However, it's far easier to simply breed/get another Kingdra that's dedicated to a certain set. You can eventually get to a point where BP is really easy to get, but Ability Capsules don't ever become 'cheap.'
>>16522671It isn't illegal, any more than switching moves on a mon in your battle box is illegal.
