On the one hand wow that is my main complaint about using your cellphone to game is that the hardware is not built for long periods of 3D gaming and a cooling fan would make that maybe doable.
On the other hand we have deeply fucked up here for a product like this to be necessary. Smartphones are by far the biggest gaming install market. Phones can and do perform 3D graphics pretty well. People do play them for hours at a time despite the fact that they aren't really made for that kind of thing, despite not having actual physical buttons.
This is just sad to me. I am imagining someone on a bus with one of these plugged into the back of their device, trying to play a few moments of Gershin Impact, with special gloves that make using 3d controls on a touchscreen easier. Just sad