I disagree with people saying Sony shouldn't have put Bluray in the console. They absolutely should have. Yes, it was expensive initially, but only £70 more than PS4 is now. And it got price cuts soon after.
I personally took up the BluRay format when I got my PS3 and never looked back. And I only buy on BluRay, never DVD. If it wasn't for PS3 I'm not sure I would have made the jump - and I'm sure there are many, many others out there who feel the same (even if some people never used the feature)/