For me, I use them to either 1) Help play a character with a promiscuous attitude who would use sex to get what she wants (66% of my characters are females) or my guys seduce ladies like Ingun Black-Briar, Lydia, Carlotta, etc. The funny part is that not all of my characters are "horndogs" - some aren't even interested and behave accordingly. 2) Add a dose of realism if you should be overwhelmed in combat. Death is a believable outcome of loosing against a group of bandits, by that same token, being raped would also be a believable outcome if you are a woman. In Skyrim, just like with other games like it, I always have that one character. You know the type, evil through and through with no redeeming qualities that everone looks at in the hope that someone somewhere will come along, do the world a favour, and put this motherfucker out of their misery. My one character is a lying, stealing, drunken, skooma-sucking, misogynistic womanizer who is also a murderer, a cannibal, and a rapist. Basically, you wouldn't want this man to come within a mile of any woman you cared about. 3) You can marry in Skyrim, so why not consummate that union? I have a few characters that saved themselves for their wedding night, one of whom is the very first character I made for Skyrim the day I got the game. While she doesn't have "hot pants", her and her husband do fool around from time to time when she's not out doing the Dragonborn thing and their daughter is outside playing with her friends. So ultimately I think the answer is "all of the above". It does add a great deal of immersion/realism. It is kinda fun and funny to see a guard get excited that he's about to shag a hot girl. And yes, it is a way to see your darker fantasies acted out in a way that doesn't hurt anyone