I've seen quite a lot of "shell but in perl" and "shell but in python" in the wild, but also I think this is primarily aimed at "this particular utility that ships with $library would most naturally be a shell script but it's a lot more convenient overall to have a nice way to write something similar-ish-looking that shares the interpreter with everything else."
If nothing else it'll make development-side package.json commands easier and nicer, which is still IMO a net win.
If nothing else it'll make development-side package.json commands easier and nicer, which is still IMO a net win.