She's the only real protection we have from infect and toxic. That alone is reason enough to buy some.
They're cards. If cards are durable, you have a problem.
These cards are really the only truly effective ways to prevent infect and toxic from ruining your game. True, she's neither indestructible nor hexproof, as she should be, but we take what we can get from a the makers of a card game who seem determined to keep getting better at making things worse (and that's no compliment).