This is cool because it avoids emulation. However I think it has many shortcomings today which could all be solved by emulating a real CPU architecture (e.g memory protection support, ecosystem with tooling and Linux distributions).

By the way I have developed a similar project, WebCM, a RISC-V emulator capable of running full Alpine Linux that can be embedded in the Web browser and can reach up to 500 MIPS for some users, which I think is pretty fast despite the emulation, you can try at https://edubart.github.io/webcm/. Booting is also fast, it always boots from scratch when you open the page, so you can boot fast even with emulation.