In general, it's just plain boring. The only information conveyed to us, the unfortunate viewers, is: "oh look, they are intimate now". If there's nothing else,

In general, it's just plain boring. The only information conveyed to us, the unfortunate viewers, is: "oh look, they are intimate now". If there's nothing else, please cut short once we understand they are going to have sex. I also believe sex scenes could be really great at showing subtle personality traits or relationship between characters, a good example of "show, don't tell". But it's awfully under-exploited and often ends up as a cheap filler...