Same as the point of high level languages generally, you can express more complex application logic with much less programming effort plus you can focus on your

Same as the point of high level languages generally, you can express more complex application logic with much less programming effort plus you can focus on your app instead of worrying about manual memory management crashes and security vulnerabilities. Register/memory write primitives can be easily exposed to the HLL. (Yes there are other high level languages besides JS you might use too, eg MicroPython...)