I am just blown away with how much you can do with the ESP32! I used to be an AVR8 fanbois but being able to make music synthesizers, display controllers and things like that is so much fun!
I agree. What blew me away when doing this was the realization that one can run BLE in the browser on the phone. So interfacing this is as simple as a QR code underneath and a tap on a button to control the mouse and keyboard.