Several reasons. I already have tablet computers and one is always in the car (GPS etc..) and 2 its a heck of a lot cheaper than a scan gauge ($35) I thought the mpguino was not available yet? how much is it? where do I get it from ?
The MPGuino is still in the DIY phase, but the estimated cost for that is currently ~35$ I think.
If you already have a tablet in there, though, I would say go for it. I know rick (rh77) has run a setup like this at some point (or at least I think so), so he ought to be able to chime in.
Cool for that price its an impulse buy so I will take a shot at it. My biggest concern is will I get MPG from it? its gonna give me LOTS of cool data especially tach load and error codes but I see no mention of economy anywhere in any of these software programs :-)