As the saying goes, "With great power comes great responsibility". This is especially true in the case of the UHK.
You are given the great power of reconfiguring this keyboard in all kinds of wonderful ways, but you can also abuse this power. Imagine binding every key to the letter "A" and setting it as your default keymap. As you might imagine, you end up with a keyboard that is practically useless. Time to meet the factory reset switch!
The switch from the distance
The switch up close
The switch on the PCB
Upon pressing it, the keyboard loads the factory keymap that is stored in the flash, ignoring the default keymap that is stored in the EEPROM, leaving you no way to make your keyboard useless.
I think this is one of the small touches that can make or break a product in some situations.