Hm, cmd + x does cut. Just not on files in Finder, the reason I suspect is the lack of a "forcing function" in such a case. It would for example be possible to lose files by mistakingly hit cmd + x. For other operations like this, (quitting without saving, emptying the trash etc) you get a question asking you to confirm.
Yes, it does normally cut, but not in finder. I don't see how could you lose files by cutting - on dolphin (KDE) if i cut a file and then don't paste it the only thing that happens is that dolphin notifies me of that (rendering the icon grayish) and, if i close it and open it up again, the file is still there, still grayish.
Cut/Copy/Paste/Undo is a huge UI problem in file explorers. Apple historically chose to not implement any of them (but it did have 'Put Back' to move any file or folder back to where it last was). Following pressure from Windows users, Mac OS X added copy and paste, but not cut. I certainly can understand their reasoning, and also am happy with it. It is not as if I spend hours each day moving files and directories around; if I did, I would do so using the command prompt.