Unless there are some great new tools I’m not aware of, C on WebAssembly seems about the same as C on Android. You can compile stuff just fine, and run it, but actually connecting it up to any substantial UI written in JS/Java is going to be incredibly tedious.
For a computation library with well-defined inputs and outputs, and that “just works” and doesn’t need any debugging in situ, it makes a lot of sense. But I think business logic by definition is going to need a much richer interaction with the UI, and that’s what makes it hard.