It doesn't prove anything, really. 22k is still really low and its unlikely to maintain even that level of sales. The game itself is also unlikely to have legs as it isn't a very popular IP and the install base is too low to support it.
We've seen it with Vita. It gets a semi-big game once in a while and it gets a nice boost only to drop back down to "normal" a few weeks later. What's the next biggest Wii U release that can actually make any sort of difference?