I think the original question was "what's so hot?"...
I think a facial is sort of maybe a bit like water sports- if you like the other person and are playing with their most intimate body parts, maybe you want "a piece of them."
It's fluid exchange, and/or "getting marked" by another person as someone's "love property"
Feeling that you stimulated them to allow yourself to be the literal target of their affection, and having your skin respond to the warmth of a cumshot that is quite warm on delivery... and likely smelling the strong scent deeply if the load ends up on your upper lip under the nostrils...
I've only indulged a couple times, but when I have to me it's not degrading at all- because I wouldn't get with that person in ANY configuration unless I was fully prepared to give and take as the passion is offered.