I would worry about the connector cable interfering with the drivers feet. A lot of OBD2 ports aren't in foot friendly positions. Pretty incredible app, but I'm missing the point. 99% of people have no idea where the obd2 port is, or what a code is, or what a monitor cycle is.
Seems like it might be using Bluetooth. I had something like this on my personal car, but it was an off-brand and stopped transmitting within a few weeks.
I would think the average driver could gain a lot from this product. First of all, it says that it can help you locate your car after you park it. I'm not sure how well this work (if at all) in a situation like a parking structure, but I'm sure some drivers can find the merit in a feature like that. The accident notification feature is yet another thing that people who live in more rural areas may find useful. On top of that, it'll show codes. Most people don't know how to check for codes, so bundling that feature in with the other ones I mentioned may broaden their horizons. For most people, I believe driving stats would be the secondary reason why they would purchase the product. Maybe it helps them learn how to drive more conservatively? Gas prices in the states are still pretty high so it may come in handy to know if your driving habits are contributing to unnecessary extra expenses.
For us enthusiasts, this doesn't seem like a step up from an app like Torque which would have all the stats that we would deem important (i.e. oil pressure, egt, oil temp, etc.), but this is definitely marketed towards the mainstream. Time will tell if people will actually want to buy and use it though.
-Andrey