What benefit does running another program offer when the program running the command (shell) already provides that functionality?

Watch also clears the terminal between runs

I guess that'd be a detractor, as he wouldn't've been able to make his post showing his results over time.

I'd've said the benefit is that it's simply a concise single command instead of a "while true" loop and a "sleep 5" command.

That logic seems to apply to quite a few basic utilities. For that matter, the shell is turing complete so ...