I don&#x27;t think that phones are secure, but people do use them for things like 2-factor authentication.  I suppose that it is the form-factor that is more relevant, since most phones are smaller than a TI-83, so much so that people are willing to carry them around everywhere.<p>Ultimately, what I envision would be a cross between a Blackberry (size, QWERTY keyboard) and the TI-83 (focus on being a simpler, lower-end computer).  Heck, one may as well give it a unix-like OS and leave out wireless communications and sophisticated graphics.  I think this is feasible, but the market would be quite small.