A very old and beloved pig, but still alas, a pig.
It's great to extend the shell idiom, to patch up its inconsistencies and unportabilites, to make it better. I love the progression of sh, csh, tcsh, ksh, bash, zsh, fish, and others. But it's also Sisyphean. At the end, you still have a shell experience not a programming language experience. And as long as we're talking about programming things, the full toolset will remain more direct, more powerful, more maintainable—and thus more apt.
I hate gol-lumping over the gap between a dashed-off Bash or Zsh script and the Python equivalent (say), but the full language has better semantics, typing, exceptions, modules, data structures, expressive power, and tooling. As the person who not only has to dash off the initial POC but extend and maintain it over time, and someone who's tried both routes, if there's any complexity at all—any datetimes, timestamps, or timezones to be wrangled; any complex JSON to be parsed out of an API; any significant parsing or concurrency to be managed—going to prefer the full tools every time.