It's only good for ppl who want early access to movies before they are added to regular prime subscription. Otherwise if you check for older movies, the same movie is available for free for prime members and on rent for non prime members (even prime members can rent, but no sane person would, if it's already included in their membership)
This is useless. Useful would be if we could rent and TV shows that aren't available. Take Glee and Monk as an example. Only useful thing about it now is ability to rent and watch movies available on Netflix for cheap in HD.