While I think there’s probably a niche adult market for these kinds of stories, I’d be surprised if a lot of the public isn’t there for the softcore T&A that tends to predominate these kinds of games. But, in general they’re games that are easy to make and that are basically digital choose your own adventure books, so plenty of room for gimmicks in that category. DDLC apparently has some neat meta stuff on it so it’s probably the exception, but generally those games play it painfully straight.
I’ll add that these kinds of games have been around since forever, and that they’re proliferating in Steam now but that they’ve always been a staple of Japanese videogames. Games with a ton of linear story chock full of stereotypes tend to fit very well over there.
EDIT: Having watched some videos of that game, I can confirm it’s pure creepypasta material that plays with the expectations of the people with its façade of a harmless visual novel. Kind of a stroke of genius considering how far it takes things.