As far as I know, when people freeze cookie dough it is for storage purposes.
Chilling it in the fridge is different though and many people do this when making rolled cookies to make the dough easier to work with. (room temperature dough falls apart and is often too sticky to roll out)
Like grumblebee stated, if you make cookie dough and try to roll it out without chilling in the refrigerator, it's too sticky and gooey to work with. As with drop cookies, it won't matter as you are scooping it up with a spoon and dropping it onto the pan.