The problem is the belief that is hardwired into the humans basic instincts about balance. We see the bike and we see balance problems and danger (not that this doesn't have that) but they probably thought of that and are working on it.
The uses of this will replace the need for books for most tech-users. Instead having a book to read, a lot of people would listen to audiobooks on their players. Now, instead of having a physical library of books you now have a digital library of books, notes etc.
This seems to be the natural progression of reading.