I suppose it's pretty easy to see why when you consider what the most^[I could be wrong, but searching for "zsh" on GitHub and sorting it by most stars should be a pretty good metric.] popular plugins are for the popular shell zsh:

• zsh-autosuggestions
• zsh-syntax-highlighting

Both of which literally start by referencing fish in their respective READMEs.

And where zsh requires plugins to get these, fish has these by default. Perhaps unsurprising as fish stands for Friendly Interactive SHell. As such, the niceties don't stop there.

Basically, if you want a no-nonsense shell that gets pretty much out of your way and comes with excellent defaults right of the gate, then you simply can't go wrong with fish.

Take this from someone that stubbornly tried to bend bash to my will with stuff like ble.sh (link) and later zsh with zsh-quickstart-kit, but to no avail... It always caused more trouble than it was worth. And when I finally gave in and tried fish, it was pure bliss from the get-go. The rest has been history... Fish has literally become the first thing I install on all my systems.

Note, however, that (as per fish' documentation) you shouldn't change your login shell to fish. This blogpost by a CoreOS engineer goes over it in more length.