Oh, I do it all the time. It allows me to write a script that I can just run from the command line when I want, like 'fetch_new_images'.

I especially love it when I'm first coding, cause I like to test as I go. That allows me to run it to see what works and what doesn't.

When I'm finished, I know that I can just plop that file into a directory and use it as a library afterward. The majority of the code that I write implements that, and I find it a godsend, personally.