It saves you time if your only goal is to put the bishop on that diagonal, but if that's your only goal, you'd be playing a very short-sighted Ruy.
It also saves your opponent a bunch of time too since he doesn't have to play a6 and other Ruy moves.
It's just a different opening.
Everyone says that the Ruy Lopez is so popular because it is so rich in theory... but for whom?
Everybody says that the bishop becomes so powerful on b3 controlling that diagonal, and they are right. But he chases our bishop there, and gets queenside space, and develops all at the same time. So why not put the bishop there in the first place?
Here we just put the bishop on that diagonal in the first place. Saves us a lot of time. What do you think?