They're right and they should say it. You would think I was insane if I made a CLI tool worked by fetching and running dynamically generated pre-compiled binari

They're right and they should say it. You would think I was insane if I made a CLI tool worked by fetching and running dynamically generated pre-compiled binaries from a server for each subcommand command and yet that's what we do with erb template style apps. The API + static versioned self-contained html/css/js asset bundle is the way for anything you would reach for erb for.