1: Not sure what your point here, if you dont want soldering, just use jumper wire, it is not exclusive on rpi.

2: What i mean is the main reason they use Rpi because it can run Python(at least easy, this was before CP/MP mature). If they had spent some effort in C, they can get away with not using rpi.

3: I agree with that, but i really do wish they step out of their comfort zone a little more discovering what is possible.

4: I dont think esp32 is overkill, it's the cheapest and easy to acquire wifi MCU, if you have better suggestion i would like to learn, there is esp8266, but the cost different is not that much.