Because Fallout invented perks.
Well i didnt play Baldurs gate and what not, but i actually dont remember seeing perks like that in games, assuming we are talking the original fallout and not this fps fallout they created.
But who cares perks is a nice addition that help you personalize your character, why not use it.
And oblivion had perks as well, you just couldnt pick them yourself.
But like i said, i was a Fallout fan, it wasn't really until Wow i startet to get into Fantasy games.