In a deck with reliable Confuse, like Spider-Man (Miles) or Gambit, you'll probably be able to play Spider-Woman for 2 with a confused villain a lot of the time. To get beyond that you'll have to confuse minions, which means leaving minions in play in order to confuse them, and confusing the villain is a lot more valuable than confusing minions, so you might be able to play her for 1 on a lucky day but 0 is highly unlikely. Outside of a deck like that, Spider-Woman is definitely not worth it, as there are a lot of better 3-cost allies in both Justice and Basic.

But the thing is, even if you do get to play her for 2, she doesn't do anything special besides thwarting twice (or attacking once) and then defending, so even then I don't really think Spider-Woman is worth considering. Even in Web-Warrior decks where you care about Web-Warriors leaving play, almost all of the other Web-Warrior allies cost 3 or less, and most of them do something when they enter or leave play beyond simply attacking/thwarting and defending. Happy to be proven wrong though.