It is true. There are two inherent benefits of AC motors - one is that they can not "run away", if the system fail they will typically just stop functioning. The other benefit is that there are no wear items other than the shaft bearings, so the AC motor is maintenance free. No brush wear, no brush dust etc.
The downside has been the need for more advanced power electronics to create the AC current from a DC battery, but with reduced costs for electronics this is becoming less and less of a disadvantage.