Okay, so this is another incredible card for Wanda's kit. No question. Just straight up canceling a card play is incredibly powerful.
It does feel like it's making up for how Wanda plays though. It's not an additional bonus. It's just helping you mitigate a downside built into her kit. She moves through her deck incredibly fast. When she empties her deck, you're dealt an encounter card. Then you draw this and get to negate an encounter card. You're not really coming ahead. You're just negating the card you keep dealing yourself.
I think that might be what I appreciate the most about this card though. The designers realized at some point in development that she moves through her deck incredibly fast, dealing herself more encounter cards, and she needed a way to deal with that. So they added this to let her negate one encounter card per pass of her deck.
Edit: Removed the part about Deft Focus. I forgot you can't use Deft Focus during the villain turn.