I have used bash, zsh, ksh, and now powershell. I am by no means an expert on UNIX shells. I could get all my work done on any one of these. My main shell is Zsh with some oh-my-zsh plugins because I’m lazy. What can you do in powershell that you can’t do in any other shell? Also, does the shell you use even matter? Sorry if this is a dumb question.
The #!/bin/bash thing (first line) is called the shebang and it can use any application not just shell, so that means Python or PowerShell or any other tool.