BTC already essentially legitimate due to mindshare. BUT I think there will be some consequences in Wall Street legitimizing it we may not see coming. There are dangers tying an asset like this directly to U.S. financial system.
There are countries that have BTC as their national currency now such as El Salvador. Turkey, for all intents and purposes, is transitioning to BTC - if you go to Istanbul airport every terminal has BTCTurk on it. And I think there are still a few whales that happen to control most of the supply. Turkey is probably doing this because of their inflation problem. Countries that have adopted as their national currency aren't exactly doing that great. Will this somehow lead to less purchasing power for U.S. citizens and increase in purchase power for Turkish/El Salvador citizens? Short term euphoria, long term consequences is the name of the game and there is no shame in THIS game.