BERKELEY, Calif. (MarketWatch) — Not everyone ran off to buy a tablet computer the minute they arrived. I still do not have one, although when I get my hands on one I play around with it, and see that it would come in handy as an e-reader or large GPS device to help me navigate the Berkeley Hills looking for garage sales.Other than that, I cannot see a need for the thing. I’m not the only one. The devices now have been out long enough in the current iteration for us to understand their usefulness. Their utility is simple, and...