I could. That requires me to have a 3D printer and be willing to invest the time in figuring out how to make a case. I don't, and I'm not.
Of course it's going to be more flexible, just like it's more flexible to design your own device from scratch. But I'd trade that flexibility away for more time to do things I actually want to be doing any time, and I'd be willing to pay quite a bit of money to get that kind of flexibility without having to spend as much time on it.
I just don't think the tradeoff is worth it. The Pockit will have a relatively small community, and you may be forced to use their software packages to develop for it. It may not be very robust or very versatile. Those are all real downsides, in addition to the higher cost.
Of course it's going to be more flexible, just like it's more flexible to design your own device from scratch. But I'd trade that flexibility away for more time to do things I actually want to be doing any time, and I'd be willing to pay quite a bit of money to get that kind of flexibility without having to spend as much time on it.