I've never figured out why this is almost obligatory in porn. Especially when the guy pulls out and then jerks on his cock until he shoots on her face. I've never done that nor ever wanted to. I have, however, pulled my dick out of my partner's pussy or mouth to have her jerk me off, and I've pulled out just as I was starting to come (sans hands), but that's something different. Besides, it's always way more enjoyable to come inside someone, as opposed to on them--at least for me.
As per the empathy thing? I don't need to see spoo shooting out of a guy's dick to realize he's coming. Maybe it's to show that he really came, and wasn't just faking it, but I really don't need to know one way or the other--like porn was somehow reality.