federer never learned 2HBH cause he can't use that stroke for his life. But there has to be some advantage to 1HBH is one of the most famous players in the Open Era, Sampras, found it to be better than a 2HBH.
For those that want to make really looooooooooong, booooooooooring rallies, the 2HBH is great. But for people that wanna make an exciting net play game, the 1HBH is the way to go
