With an AMS 2 Pro sitting on top of a P1S printing ABS in a 30 degC environment, the interior of the AMS gets to in excess of 43 degC @ 33% percent humidity.
This passive heating would create passive drying by having the AMS drying fans running (without the active heaters) to circulate and exhaust humid air to both lower the internal temperature and passively dry the filament in use.
In reality there is NO difference between this passive heating and active drying except the passive heating is wasted utility without the drying fans running to expel the humid air.