It is useful for those things. I implemented a fairly involved scripting system that we now use inside all of our server instances. Each script in the system is an entry file mapping to an alias command and the entry file is invoked from the top level. To get the benefits of async/await, we write the logic of each entry script under main = async () => do_logic(), and call it at the end of the file as main().

I just don't see how this workaround is the correct solution. Just saying that's it's generally a bad idea is not enough for me. At some point there will come a time when you want to treat a file as a function, and when that day comes you will want async/await at the top level.