I honestly don’t care if they do or don’t add this stuff, but please make it skippable. The last thing I want is some boring corporate-approved formulaic bland sex scene that I have to suffer through in the middle of an interactive game. At least movies and shows let me 30-second skip past that stuff. All of them are exactly the same sequence. It’s tedious.
As for flirtation being more important to in-game social interactions and dialog trees that could be fun. It could also set young people up for trouble. They’d be practicing the “wrong habits” that will get charges filed against them IRL.
The reason game designers are afraid of sex is because most of Western society is. Can games help turn that around? I don’t know, but probably not. The USA is super puritanical about all things sex (but blood, gore, and violence are generally OK).