This is very technically impressive but it seems pretty niche to me.

This has roughly the performance and safety characteristics of something in the Ocaml-Golang area, but with C's extremely limited ergonomics, and I don't see why you would want that. I suppose it could be used as an ASAN/UBSan on steroids during the debug phase and then switch to a faster implementation in prod? Other than that the use-case is existing large-scale c/c++ code-bases, where safety is critical and speed isn't. How many of those exist