Optical is Terrible, But...
http://arstechnica.com/information-technology/2014/01/why-facebook-thinks-blu-ray-discs-are-perfect-for-the-data-center/ Both Amazon Glacier and Facebook use bluray media for long term storage. It doesn't degrade at all like DVD or CD since it's a completely different process. So, it has some serious potential. However, DVD and CD basically suck so hard that they've given optical media a (justifiably) bad name.
If we WERE to use bluray media, it would probably be best served as a complimentary storage method, especially since its initial cost is so low (~$50 for a home writer plus the per/tb cost is relatively low)