[setuids]

> The only time I've ever needed that was because I'm copy/pasting something from the internet, which I probably shouldn't be doing at all, and at the very least not with such frequency that it effects my decision of which shell to use.

It is nice when you generally write {POSIX,Bash} scripts, and decide to quickly throw something together in the interactive shell. I find myself often putting $(), before realising that I need to remove the $ to make it valid in fish. But yeah, i think it's mostly to make shell scripts of the internet work OOTB.