Yeah, I would agree that setting zsh as default shell would be a bad idea, it's here just for example purposes.
On the other hand, I've already encountered an issue when I've set shebang to be /bin/sh and after googling for a while I've found that preferred shell for scripts should be bash as basically bash is sh, but with more features and better syntax.
So, I would say that:
is maybe a better solution.
Unless your audience doesn't have bash...
Do you really need the additional features for your scripts?
Well, if you put it that way :D I guess you're right. Nevertheless, I don't think that I will write scripts for other users than me anytime soon.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.