There is like a lot more connected functionality coming with it in future firmware updates. I would expect the Navionics to be connected to the web and synch to your phone or a cloud based interface to post process the marks and notes and share them between all your devices.
Also, I doubt the tablet will allow you to do anything other than what they want, could be wrong, but I don't think the tablet is going to run as a "tablet" as we see at the Verizon store, more so it will be a proprietary UI and only do what they want it to.