Awesome! FWIW I currently use a clone [1] of Andy's notes website [2], to which I've added KaTeX support. The biggest feature is the Roam-style bidirectional linking. But your system is sufficiently simpler that I think I'll give it a try, at least for some use cases.
Roam-style bidirectional linking would be cool, but I wonder if it's better to keep it simple for everyone else rather than add very specific features for the few people like me. Your call...
Anyways, cool project! You're definitely making something people want :)