What's the point?
For consumer playable multimedia, I don't see much point in this. Frankly, I think DVD is good enough for most people. Hell, VHS was good for a generation, and people stayed away from the superior Laserdisc technology in droves. (And SVHS, for that matter.)
High-capacity discs are nice and all, but as several people pointed out, as long as they're vulnerable to physical damage you're just putting more and more data in danger at once.
And while it's got a great WOW factor, cranking up the resolution on crappy movies and TV shows just means you see how crappy they are that much better. Even good movies that weren't made to be seen that closely are going to show their blemishes more clearly.
Shouldn't they be working on improving the content first, then worrying about getting a wall-sized TV into everybody's home to watch it?
As a read-write medium this is useful. As a read-only medium? Yawn. So you can pack the entire LOTR trilogy on one disc, with all the extras, at super-high resolution. So what? That just means more menus to go through when you insert it.
And more advertisements. Yay! Every time I insert a tape or disc now I get 10 minutes of ads I have to bypass, plus 2 minutes of FBI warnings in 13 different languages, plus another warning, plus three logos with fanfares. And then another ad, like as not. I rip DVDs as soon as I buy them and copy the main movie to a new DVD just so I don't have to go through that horsecrap over and over again.
16 layers means 16 times the room for advertisements and useless nonsense.
Not that I am bitter.