That's odd. I swear I had cut files before. I just find it much easier to command+X on a file, going to the destination then pasting. I don't really like dragging files through folders. I mean, what if you are say 20 folders into something and you want to drag a file into the previous folder? If you drag you have to go all the way through those folders again.
Ah well. Maybe cutting files will be a feature with an update someday...