From what I see these games simply use LLM apis, not some kind of sophisticated NN mechanics handling the decision trees.
They are not new in that, I have seen a couple of games that were basically slop (and terrible games, judging them as games) wrapping chatgpt.
Wanderfolk seems does not seem particularly inspiring, even the trailer has terrible audio mixing (there are times you cannot hear the narrator because of the game sounds, it is either fully made by an llm agent or by humans that do not seem capable of making a game if they cannot even make a proper short video) which does not make it feel very promising. Everything seems ai generated in general, and more like slop.
OMEA seems a bit more decent, and I would be curious to try it, but I do not like its visual art very much (it is ai generated "and curated by an artist" and it actually shows), and in particular the ai generated images of humans. Irrespective of what I think about ai image generation in art in principle, I think there is a deeper problem here as a game in (broadly) the visual novel genre must imo have a distinctive visual style, and their images just reads as ai generated (before I even read whether they are ai generated, it is that obvious). In general, I find this style of ai generated images of humans very offputting/uncanny (other assets, backgrounds etc I dont get bothered aesthetically as much) and I think I will find it hard stay engaged for long with such a game. Regardless, it seems a more decent attempt than most others I have seen. They do employ writers etc at least to create narratives, so it is probably not a total slop (otherwise, I can just roleplay with chatgpt directly or whatever).
In any case, these games are closer to being "llm wrappers with a certain harness" than having some actually new and sophisticated way to handle decision trees. Another issue with these games is that they do not even use some finetuned local llm, but use apis to providers, with which I am not that comfortable either.