>>14366592yeah you can theoretically build medical systems which communicates over bluetooth to your smartwatch. like full body ECG with transmissions to your smartwatch. would be great for workout analytics and much more. bluetooth
pic related has bluetooth receiver and transmitter. it's the smaller one.
https://www.lucadentella.it/en/2018/06/04/il-piu-piccolo-modulo-esp32-per-ora/