But as long as you only execute programs a script for cmd, bash, PowerShell and a number of other shells looks pretty much the same. In PowerShell executing a program is simply to state the program name (barring spaces in the path for now). You don't have to do something like execute_program(name, args, input_redirection, output_redirection, ...). Well, you can, if you're so inclined, but it's usually unnecessary. Any shell is "just a REPL for a scripting language". Interactive use is one of the tenets of a shell, otherwise it's more a batch processing system, I guess. And just like in other shells the language is one geared towards running commands (cmdlets or external), managing their execution and processing their output. That it works better for general programming than many other shell languages (in my eyes) is a nice bonus.

Heck, running programs is even easier than in most other shells since there's a specific token that stops argument parsing completely which means you don't have to care about quoting at all (an ever-present nightmare at times).