This is hardly a porn game. You have to play for several hours before seeing anything and often times, the sex scenes add to the character and are quite tame (Minthara's is the most explicit, everyone else's though could be considered PG-13 if it didn't have nudity).
Sex is used to enhance the intimacy of relationships or to show the callousness in characters and I believe BG3 did that pretty well.
I agree with Zentu. Enhances how? Sex serves no purpose and the character development stays the same even without sex. The only thing it serves is for marketing. When you want to see it done better look at Arushalae in Wrath of the Righteous where having sex, or at least the possibility, is tied to her development and her fear of falling prey to her succubus instincts.
BG3 has nothing like that. Sex is (early because of EA) payoff to attract certain kinds of players, nothing more. And Larian made sure everyone knew it by prominently showing (bear) sex, genital customization and kept talking about sex, intimacy coordinators, ect.
I guess we all have our own views on what does/does not lend itself as a benefit or enhancement to a game.
If looking for strict utility, then the sex scenes do nothing. No extra abilities or items. You are correct.
But for people like me who play RPG's for rich character progression and story purposes, it enhances a lot.
You mention Wrath of the Righteous where sex is a prominent thing tied to the development of a character and, in my opinion, that's exactly what the sex scenes of BG3 achieve. You are, of course, fine to disagree.
But when looking at the character of Astarion, who's whole life is about control and his inability to have agency over his life, a person who's body was literally used as a tool for someone else's gain, a person who's first defense mechanism is to seduce and enthrall as an instinct, his sex scenes are all about learning that side of him. He literally talks about how his seduction of you was all for protection and then his journey afterwards is helping him reconnect with his intimate side without needing sex to be a weapon or a tool for control.
I'd say that qualifies as character information you wouldn't connect with nearly as strong without his sex scenes.
Sex was definitely sold as a marketing gimmick and there are definitely less mature players out there playing the game solely for the sexualized parts; that we can agree on.
But for people who thrive on getting to know characters and who crave knowing just that one extra detail about a character that we otherwise would not have known, the sex scenes do that and then some. So it's incredibly immersive from that point of view to have these scenes.
