If PS3 doesn't have a blu-ray then it would have (should have) been much cheaper.
Movies for blu-ray is hardly out and you would probably get a poor line-up of movies especially that DVD market hits a sweet spot & you can get DVD player at Tesco for £18! (Even cheaper than Blu-ray movie?!)
It doesn't benefit games at all, especially that it's slower than DVD drive so developers would be struggling get amount out of Blu-ray in reasonable time! It means a longer loading time!
All of this is so unnecessary but then, knowing Sony, they have pushed their luck too hard with their format!