Should be a game feature or nah?

I'm thinking of having the ability to undo the Breakthroughs of characters can be a huge W in my opinion. I say you want to get more vballs when you're short of it and then you have a character that you don't use that often and you want to undo it's breakthrough to sell it for vballs.

ALSO I WANT MY SIWOO BACK, I ACCIDENTALLY DELETED IT😭