This seems too good to be true..

I'm working with a 30 minute movie that I want to split up into 3 parts (for youtube). Usually I would open it in a video editing program, select part I'd like to upload, then re-render. Rendering a movie would take hours on my computer, then a friend of mine mentioned self-contained movie in quicktime. So I tested it out. I split my movie into 3 parts in seconds, with no drop in quality. This doesn't feel right.. nothing should ever be this simple and convenient.

So my question is.. could I just upload all 3 parts I made with quicktimes self-contained movie feature and encounter no problems? Or will the black magic Apple used to make this work cause problems for anyone trying to watch it without the original file?