With a 16GB memory card just a little more that's a whole lot of PS Vita and PSP gaming, plus PS4 Remote Play, PS3 games via PS Now (with a subscription) all on one tiny little box.
While the PSTV may struggle to compete with the latest Apple TV, Chrome and Android devices and so on, the sheer quantity of gaming greatness from such a tiny box makes it a great bargain and easily affordable to bolt multiple boxes to screens around the home.
Will Sony kill the little box once it has cleaned up on these sales? Hard to say, given its lack of marketing and interest in the Vita, but things don't look great.