Yes that's what it's probably for, I've found this discussion:
http://www.wirelessforums.org/uk-telecom-mobile/latest-googl...
Though others claim that for calling it launches the phone app, and doesn't call out itself...
Anyway -- it is just a pretty harmless example. Some games are much worse. I don't have time to research or decompile all interesting apps to see what they are doing with a certain permission.
I never call from my map, so don't want to grant it. It may also use the permission for calling premium/foreign numbers behind my back and cramming my cellphone bill. I don't like the "Accept it all or leave" approach.
But even so, I agree that the permission system is so generic and creepy, and sometimes you freak out when you see some (probably harmless) permissions, because you don't really know what to expect, and you don't know what kind of power Google has given to developers through these permissions.