Hairdryers are capable of electrocuting people and are used in generally wetter conditions and run on mains power. Trimmers are used on dry bodies and use safe DC power from an adapter. Why are hairdryers not using adapters, especially when they are used in more dangerous conditions?
I can guess these reasons:
- Trimmer cables are detachable from the body and harder to insulate
- Trimmers have chargeable variants, so they are designed to run on DC
- Trimmers will be unpleasantly heavy with integrated chargers