I've been using fish for longer than I can remember, but I almost never write fish functions. The out of the box experience is already much better than bash/zsh (out of the box, not including plugins/etc).

I also prefer the basic syntax for things like for and while looks on the command line, the way they get formatted. With bash I always had to look up the syntax because I didn't use it much. Fish, I barely have to look up things because they are pretty intuitive, for the most part.

Also, no adding `export X=Y` to your .bashrc because you can just `set -U` and it automatically saves it between sessions.