Part of my concern is the RAM module; I'll assume that the specs infer that it has a single DDR3-SODIMM slot, which is good for keeping costs down. Overall, I wonder exactly how adding on the RAM, and other expanded functionality will affect the formfactor: 10x7cm is nice, yes, but if adding important things like storage, RAM, etc require bulging the form out in all directions, then it's nowhere near attractive; at that point it becomes a question of "what's the point? my 10x7cm board became a bulky 20x20 cm!" At that point, the 17x17 cm size of Mini-ITX would be better, since none of its expansions require putting anything other than DIRECTLY ABOVE the motherboard.
Of course, I can see that a lot of others have picked up on cost being a big question: if this thing is cheap, AND can retain its compact formfactor once expanded, I could see this being popular for embedded systems, especially, it seems, from a segment of enthusiasts who got bored of DIY desktops and now want to do DIY embedded systems.