The comment I was replying to said This would be no different than having two histograms side by side. And I pointed out that it is not.

Oh well I'll answer your question anyway. Because 90% of everything is crap (probably more than that on P2P sites). Re-watching a movie can be like walking in the same park more than once, looking at pleasant things with a sense of recognition. You could put a movie in to suit your mood. Sometimes you'd rather watch a good "original" movie again than watch yet another crappy remake or rip-off.