For ambient computers to be viable products they need to be inexpensive, easy to control, safe, accessible, and, most importantly, they need to be socially acceptable to use. Glass is none of those, but it would be a great success as an experiment even if it serves only to illuminate the issues as tough problems facing the future of computing.
Couldn’t have put it better myself. The biggest hurdle to success with Glass is not technological but rather psychological and sociological in nature. Technology has reached a point where it is feasible to produce these devices, but whether we as a society are ready for them is an entirely different question.