I don't really see anything wrong with that kind of story in theory. It's not like there is anything more deep about namedropping and fumbling around with philosophical concepts that seem to make a story "truly great" in the eyes of critics.
It's only unnecesary when you write a story that has nothing to do with sexual themes and then add a gratuitous sex scene as a type fan service. This would describe many movies in the 80's and 90's but doesn't describe movies like Sex is Comedy, Showgirls, The Lover, or Titanic.
If you take a VN like a Type-Moon such as FS/N or a Nitro+ title like Saya you find stories where the relationships develop enough in ways that a sexual relationship is plausible. To state that stories like that aren't meant to have sex scenes is to imply that they are intended for young teenage audiences. The sexual scenes are meant to be adult scenes which enforce the gravity of the situation and mature consequences the characters face: People die when they are killed.
There is no "fade to black" in real life unless somebody drugs you.