I can see the contextual bit, but I'm not really sold—at least, not yet—on the HUD form-factor. Why can't I view the smartly-pulled-up, contextual information on a smartphone screen? There are a handful of situations where no-hands usage would be nice, but for the most part a screen works fine for me. There are lots of things I'd like improved about quick, non-frustrating access to information, but they're mostly the software/indexing/querying/"smarts", not the display technology.