I could understand this with oral sex because you may be adverse to having your mouth filled with cum. But I never saw the point if you were vaginally or ass fucking. And I think it’s demining and disgusting when guys spray a women in the face to degrade them.
Well, degradation is in the face of the receiver. Some people do like being degraded.
A “facial” isn’t inherently demeaning, or at least no more than any consensual sex act is.
As far as doing it while engaging in vaginal or anal sex, there’s practical reasons as well as the possibility of it being enjoyable for parties involved. It really is an easier cleanup than ejaculation into a vagina, by a big margin. And anal stimulation, plus the addition of semen can cause rather abrupt need for a toilet, which is not conducive to after care, cuddling, or much of anything else.
You jizz on the body, and if you’ve thought to keep a towel on hand, you’re done. You go right into whatever preferred after sex activity you want. The face is the same in that regard.
Fwiw, most things like this amount to individual preferences. You’d be amazed how often something that’s a negative to someone is someone else’s favorite.