In Delta Force map making, that is.
I personally use them, even I can do it a different way in events, because I'm so used to using variables while working with IDE's. I also find that they make it easier to have the WAC file work with the MED by setting variables in the MED for use in the WAC file.
They're perfect for working with numbers, and the simple arithmetic you can do with WAC files.
I hope in the future they let us do more with them.