It's true. My thinking was that there are some techniques that I use in both interactive shell usage and in scripts, and that using the same language for both would teach me them better. I'm trying to think what the best examples are, having run this experiment on myself for a couple of years now. I think one is process substitution with <() and io redirection stuff like <<<.

Also IIRC correctly bash and zsh differ in whether piped commands run in different subshells.

Stuff like that; I'd like to just have firmly in my mind for interactive shell and scripting and not have to know two similar languages.

But I miss tab completion for aliases.