This reminds me of approximately 30 years ago. While dabbling in ham radio, I learned that speakers can work in reverse as microphones, and vice versa.
They can, but I have never seen them wired that way in a commercial product. LEDs can also be used to measure light btw.
I definitely had some cheap PC speakers in the mid 2000s that worked as a shitty microphone if you plugged the cable into the microphone port instead of the speaker port. You basically had to yell into them, and the sound quality was atrocious, but it did ‘work’.
A surprising amount of circuits work like this. Generators and motors are basically the same as well, and spinning a fan by hand will induce current into the wire. I assume most circuits are designed to properly handle that happening, but I still worry when blowing the dust out of my PC and will manually prevent the fans from spinning when I blow compressed air at them.