I suppose they could, in theory, negotiate a better deal with the nic.io folks, with the pitch that making it easier to register domains will increase overall registration. Like you've said, nic.io isn't the most user friendly experience. I stopped myself a few times when registering, wondering if I was indeed on the correct site (because the official domain registry for a TLD couldn't possibly be this awkward).

I guess it could be if they were to be able to buy in significant enough bulk (although not sure how much of that is already factored into the price): http://nic.io/join.html#benefits