Nintendo says the NX is a 'Home gaming system'

[JEMC]

The wording used makes me think NX is, indeed, a tablet.

Most of us won't take a tablet like device that only plays games outside. No, we would carry it across our home, playing wherever we want, thus making it a "home gaming system".

Also, one of the most liked features of Wii U was the ability to play on the Gamepad without the TV, and I wouldn't be surprised if Nintendo picked that idea and improved it, with NX being basically a hardware powered tablet/gamepad to play wherever we want with a dongle or dock to stream the game to the TV. Of course, such tablet would be very power hungry, which would explain why Nintendo calls it a home system, as you'll need to plug it quite often.