Organization purposes. The entire purpose of religion is to organize people under a common belief. If everyone prays to random directions, its all chaos. Religion is all about maintaining order. It might not make sense now we all live in very sophisticated, organized societies, but we came from anarchy, and religion is derived from the fear of said anarchy. All civilizations have had some form of religion in common.

Islam came from a very tribal, disorganized place where everyone pretty much did as they pleased, especially the stronger. And so Islam has rules for everything to avoid specifically that.