Laptops work when plugged in without a battery. Both drawing power from a battery and charging seem to heat them up, perhaps both at the same time would exceed

Laptops work when plugged in without a battery. Both drawing power from a battery and charging seem to heat them up, perhaps both at the same time would exceed their thermal limits or at least degrade the lifespan of the battery. I suspect devices that work while plugged in have circuitry that entirely or at least partially bypasses the battery to power the device. Then I guess it's a question of if the intended usage of the device can justify the additional complexity/failure modes/cost of the additional circuitry.