That may be true but given the rise of digital sales in the gaming industry, Nintendo cant expect us to fork over as much as the system itself to have a decent library of games digitally. I mean sure sd cards can hold a lot of data but their also really expensive when compared to USB HDD. If the tablet holds a memory card slot and that's the only way to expand storage, then that's a really tough sell for Nintendo.Nintendo says that all the hardware is in the tablet itself, and the dock just provides the TV connection and charging. And obviously also the USB ports, but they don't seem to be officially acknowledged as being there.
Given that the system memory is only enough to hold one full size game though, I'm sure it has some method of expansion.