So what uses a CR2032 battery11 Apr 2018 20:31
Well after a quick search theres;
powering blinky led lights- like a bicycle tail light
bicycle speedometer
Real Time Clock module backup battery
It can power a ATtiny 85, which is a small 8 pin microcontroller
Most motherboards have a CR2032 as the clock/bios battery.
online banking card-reader uses a pair of them.
ukulele tuner uses one.
pushbutton for a wireless doorbell.
Many single use medical devices that require LED illumination use them. Proctoscopes and rectoscopes as well as single use laryngoscopes often have them.
Watches
Bathroom scales.
Key fobs for cars,
Laser pointers
Calculators
Pace makers
... well you get the idea ;) a dam lot!!