There are literally thousands of people mining bitcoin on ESP32 devices knowing the chances of mining a block are just about 0. It's just about having fun and education.
The fun is on the seller side, the education for the buyer is " I got ripped off".
There is nothing to learn by buying an ESP32 Miner, not even building and programming it.
If they wan't fun and education they buy an odroid and learn to program that thing.