Why would you play this card over dark confidant? Also, I don’t think any deck runs even a single Confidant, let alone confidant #4 which is still clearly better than the first copy of this card.
It’s a cool card, just not vintage or legacy playable.
You will constantly be flipping over cards that do 0 damage in vintage. The only exception would be force of will.
Trying to trigger ninjutsu makes your deck bad.