Yesterday I had the chance to experience 3D without glasses on a Japanese mobile phone (I forgot the name of the handset already, sorry).
To say I'm 3D pessimistic is a euphemism. I don't agree this brings much to movies (or games), and most of the time I end up moaning about the decreased brightness and the annoying glasses. However, on a mobile device - and this will be very much the same on 3DS -, I was blown away by the ability to see 3D content without wearing anything.
Watching 3D with glasses is like seeing a magic trick knowing what the trick is. Your brain can't help remembering that the very reason you can see piranhas coming straight to your face is related to these glasses. Your first experience of 3D without glasses, however, brings you where we've always wanted to be: the ability for images to come to life like never before, almost as if they were meant to.
The promise of 3D is there. Seeing Tron in IMAX 3D was already an experience impressive enough to realize that there is something worthwhile pursuing with this technology, beyond just the commercial value of more expensive content. But with the ability to watch 3D without any glasses is clearly going to be a huge shift, one that will impact dramatically how we produce content.
As mobile devices are the first able to produce the 3D image without glasses (at least for the next 2 to 3 years) I wouldn't be surprised if we saw another huge increase in mobile content consumption over the next 5 years, since for the first time in history your experience may be better on a mobile platform than in your living room, and not just a dumbed down version.