Thanks for your feedback! This is the reason why we posted our work on HN. I really appreciate it!
You won't believe, storing Nots data as a separate git repo or as a metadata was our initial thought when we were starting the project. But it quickly became clear that it's too complicated, pollutes the repo, hard to query. Lots of downsides. But we know that everything you entered is your data, and we cannot lock you on the service. We're thinking of one-click export of your current docs snapshot as a nicely formatted HTMLs. Maybe even make a recurring task of sending such snapshots by email once in a while. Will figure it out. Stay tuned.
As of prices, it's a fair point. Now it's clear that we have to review per-user prices. And you're right, something around $100/y is fine. Thanks for your suggestions!