From a writing perspective, it's much easier to make a character interesting when you can give the player the option to actually get to know them romantically just like they would want to in real life. which are big enough to warrant their own guides, were not nearly as prominent as the rest of the game's features, yet the biggest takeaway among many fans was the romance aspect.
It connected them more deeply with the characters than any other parts of the game. If you didn't know the games and you overheard most of these in-group conversations, you'd honestly think they were all playing pure dating sims.
You might think of dating games as only being the Japanese ones where you play a cute girl and you have to go on dates with handsome anime guys until you're able to win one as a boyfriend.
These are the typical otome dating simulation games that started the trend (otome meaning "maiden" or "girl" in Japanese).
But as social norms shift, Western dating sim players are multiplying and becoming more open about their love lives and love of the genre.
In 2014, it was reported that over 22 million women worldwide were playing dating sims and most of this comes from the genre's increasing accessibility outside of Japan as well as Western developers making games patterned after them.
You can slay your dragons and shoot your aliens while also developing real feelings for an artificial companion that may or may not lead to a sexual encounter, all of it presented in a way that feels mature enough that you don't have to feel ashamed for enjoying it.