Would this be the same on games like house party with animated theme? or like simulacra with real life scenes?
IMO you'll find it hard to beat visual novel games available on steam.
You should consider that bitcoin have a transaction fee (compare to steam, often one time payment) and I'd think it will be a great deal for users specially when they need to pay chapter by chapter or scene by scene.
I think so too, the existing visual novels (I'm assuming graphic novel games are the same thing) will be hard to beat in terms of production quality, these guys have really high production values in their products, but I personally feel you could still beat them in terms of original content.
Yeah, I know, it almost goes without saying, but I think there's still a lot of room to explore in diverse storylines (culturally and geographically) that readers haven't had the chance to glimpse in popular titles. Writing styles are also still pretty much North American, or with Japanese/Korean influence. I bet you'd find a huge market in Latin America, for example.