Looks interesting and I gave it a whirl-- thank you. Your intro mentions filter + sort, but I couldn't find a way to do that in the web UI (maybe that's just my ineptitude).

Re your question whether it would be useful: hard to answer because I cannot tell right now whether it solves (or intends to solve) any specific problem better than plenty of other alternatives.

This is a really interesting approach to data manipulation! Local-first tools are becoming increasingly important, and the visual feedback loop you describe sounds very intuitive. The fact that it runs entirely in the browser with no server dependency is a huge plus. Looking forward to seeing how this evolves!