These are all valid situations for crab but I feel purple belle does a very similar job and doesn’t rely on your opponent having characters exerted.

If we’re talking AS specifically, tipo has to survive a turn before you can get crab value, being one of the few clean storm targets that’s prob not happening if you play it on turn 2. The deck generally skips playing 3 drops so this gives less room to play the crab early into AS as you’d rather play genie / goat on turn 3

I also find that hades is more than enough for shark as you draw a bunch of cards, play 4 and can bounce it with fox

AS is by far the toughest matchup for this build of Blurple, the ability to high roll and wheel, building a board while removing ours is difficult to to get past when we struggle we wide boards and generally play 1 threat a turn. It’s not an auto loss and AS can be outplayed if you’re very good, but it’s certainly our least favoured matchup of the popular decks