It's 'easier' for some people but you lose GNU bash compatibility and it kinda underlines all of the issues with interactive only shell systems -- a lack of interoperability.
It's honestly a non-issue in the current year to learn zsh or tcsh
It's honestly a non-issue in the current year to learn zsh or tcsh
Compatibility has also come a long way in recent releases; you should give it a try.
Try this (tested with zsh 5.9 on archlinux):
foo='PWD[$(echo hahaha >&2)0]+42'
[[ "$foo" -eq 5 ]]
I'm pretty sure zsh has an optimization where it skips the indexing if the variable doesn't exist, which happens to sometimes stop this. But since you can just reference variables like PWD, that you know exist, it's not really a security improvement.