Clips work in a different way. They are used in multitrack and when you create one and spilt it, you aren't actually 'splitting' the file at all - just the playback of it; it's still one file. That's the essential difference between the screens; multitrack is non-destructive - if you actually want to make permanent changes to a file, you have to do that destructively, and only one file at a time. A file can be a whole clip, or it can be sectioned (split) and used as many times simultaneously in a multitrack session as you want. When you do this, all you are actually doing is starting its playback in several places, and not actually altering the file at all.