The main use case here is not as much building Zig for an new architecture, as it is a way to let contributors build latest Zig trivially. Without a bootstrap

The main use case here is not as much building Zig for an new architecture, as it is a way to let contributors build latest Zig trivially. Without a bootstrap process like this one, it could happen that you run git pull and then can't build the compiler because it's using a new feature that the version of the compiler you have doesn't support yet. The wasm process ensures that you can always build the latest commit.