Not really, you can make .fish scripts or call "bash script.sh" when it's more appropriate to be posix compliant

Not really. I hate writing bash scripts anyway so I usually script whatever I need in Ruby which is far better at scripting than any posix script ever will be, and even when I do need to run a bash script I still can or just shell down into bash or zsh if I really really need to. But that’s like once a year.

The only thing I miss in fish is $?

I know $status exists but my fingers don’t.

Zsh has more features and customization options than bash. Fish has a ton of convenience features at the cost of POSIX compatibility (which many view as a good thing)

Once upon a time I was the person that was constantly messing with my shell. I would performance tune it, try out new plugins weekly, change my config often. It honestly became a huge waste of time. Since switching to fish I literally haven’t spent any time configuring it at all, besides adding in the fzf plugin and the fzf-marks plugin. It just works. And it has all of the same features that everyone adds to zsh with plugins straight out of the box.

If you’re happy with the default in bash or zsh then you will be even more happy with the default in fish, as it’s just much much more user friendly (which is why so many people add so many plugins to bash and zsh: to make it more user friendly). You can even configure it (even the colors) with a web interface! No mucking about in text files if you don’t want to.

I was the person who used every kind of zsh package manager that existed. I even had performance tweaks for some because they were too slow for me. I didn’t even use oh my zsh because it was too slow, and I had hundreds of customizations and maybe 30 plugins.

I no longer needed any of the plugins except fzf and fzf-marks when I switched to fish. It really did simplify my life a whole lot. I don’t ever mess with configs anymore.

That’s fair. But look at it this way, when you’re at work you’re being paid for it, and you might eventually improve your productivity.

Also, you can have a look at oh my fish, it’s an alternative to omz I used before switching to starship.