No. Nothing extra is added, it undercuts any seriousness or artistic value the game may have, it messes with esrb ratings, and gets kids addicted to porn. As porn brained as I am, I still recognize the downfalls

So just like in a movie, what does seeing the sex explicitly provide to the story? I mean if you want porn, go watch porn, but usually when adding it in to a story it tends to rip you out of the space.

Not really, no, but I'd like it if more mainstream games that include romance and sexuality actually do something interesting with it. There are so many ways to use it for character development and storytelling drama but mainstream games rarely seem to do anything more than just use it for fan service titillation. Don't get me wrong, I enjoy some of that, but it's frustrating how dull so much of the writing is.

Mainstream-targeted RPGs -- especially JRPGs -- with male protagonists tend to be particularly bad. The developers may sexualize the characters, but just for marketing. That usually stunts the interpersonal character development. If you get a bunch of horny teenagers and twenty-somethings gallivanting across the countryside, some of them are gonna shack up -- and there's no way everyone in the party would be happy with who shacks up with whom! That should create interpersonal conflict! Drama! Storytelling potential! Instead you usually get every girl in the game throwing themselves at the player -- plus or minus some with tsundere personalities -- and the rest of the party just being okay with it. How dull. Even worse, usually no one else can get into a relationship so that the devs can keep "options open" for the player and draw out "will they or won't they" for the entire game. I'm not saying every RPG should be a jealousy simulator, but... wouldn't it be interesting if the player's pursuit of a romance causes the party to break up? At least, sometimes? What if that makes the final boss nearly impossible to beat? Or, what if the player gets into a relationship with one girl and another is revealed to be a yandere -- who starts to engage in friendly fire? Even just having a set canonical love interest would allow for way more interesting story developments if implementing branching narratives and complex choice systems is beyond the capability/budget of the dev team...