I'm not sure that 'useability' is really the point here.
I'm actually more concerned about how they're integrating the 'pen' function into the toy. If it's a replaceable pen/pen-holder-type deal then that's cool, but if the pen is part of the toy such that once it runs dry then that's not so good IMO.
And yeah, hope it's way cheaper than that. I'd be willing to go up to 3000円 or so but $55 is a tad steep.