This seems purpose built for me. I ordered a foot pedal online with the intention of hooking OBS up to it. It seems to send a 'b' keydown event when it's pressed, with no clear way to change it. Utterly useless out of the box lol.
And since you are skipping the redundant USB step, you can also use dumb non USB pedals. There are plenty of options available meant for sewing machines, midi keyboards and industrial equipment. Just need to watch out as some of them contain a potentiometer for modulating the output instead of on/off switch. That may or may not be what you want. It should still be possible to emulate regular switches with them, but it will require a bit more coding.
This is more suited for moderate complexity HID devices where direct rewiring is less practical due to amount of inputs (keyboard) or size constraints+non trivial undocumented sensors(mice, barcode scanner, other specialized input devices), or don't want to take it apart.
Was it a lot cheaper than the Elgato one?
https://www.amazon.com/Elgato-Stream-Deck-Pedal-footswitches...
I'm thinking this remapper would get some buttons working on some old USB keyboards that have driver issues. BUT, the cost and time to make one of these remappers makes it only useful in very extreme circumstances where buying a alternate replacement device is not possible, feasible or desirable.
Looking at the store page is refreshing my memory. I ended up being unwilling to install the sketchy software. I just took it for granted it would come with a sensible default. Mouse3+, or a joypad input. Something.