In my op, it's one of those things that pretty much "came" into popular sexual practice from porn, a relic from the days when a porn actor's pay was often related to visible ejaculation (hence "money shot"). Not saying no one busted on anyone's face before porn, not at all, but I'd be willing to bet that it was less common or accepted.
As for my personal preference, it does nothing for me, being one of those things that--like anal sex--is hotter in the fantasy than the reality. Like sex isn't messy enough already.