I think you can just create another module that'll split the gpio to keypad and other purposes as it is just a USB keypad..
It seems like the whole point is that it's one integrated piece you can slip in a pocket, not a collection of hacker gadgets with separate chargers and USB cables you have to be careful about.
But it's not a single thing if you're carrying around other parts anyhow, and those appear kind of flimsy. And I already have a general purpose computing device with networking capability that goes in my pocket, a smartphone... so why would I want to put it my pocket if it does less?
A built in keyboard could be a failure point, and gamepads are well known to fail. I'd trust five layers of frameworks and thousands of lines of code more than a cheap switch.
If they really wanted maximum reliability, I would prefer they charge the keypad with NFC and talk to it over either BLE or just the NFC itself.