You also have to be careful with what other USB devices you plug into your computer (both internal and external). The spec is 40 Gb/s for the controller, but ports often share the same controller and the bandwidth will be split between connected devices. For some computers, this could mean that 3 or more ports should be completely blocked off when plugging your gaming USB drive in, at least while playing the game. If your PC only has a single USB controller, I guess you'll also need bluetooth peripherals.

Fair enough, I imagine the potential audience of people who both have that tech (and are aware of if rather than it just coming with their machine) and also don't have enough internal memory to install a game is quite small in the grand scheme of things and a hard sell for a publisher.