Warren Buffet is not even an "opponent" of bitcoin. Warren Buffet, Charlie Munger, Nouriel Roubini, and similar people are merely just background noise for bitcoin and cryptocurrencies in general.

Would that change their mind on their opinions regarding bitcoin and cryptocurrencies in general? It's highly unlikely in my opinion. I don't think investors like Warren Buffet likes "investing" in stuff that are high-risk, as I'm pretty sure he has a hard time on trying to understand bitcoin and cryptocurrencies in the first place.