Overview
A fast-drying towel is boring until a wet cotton towel is hanging in the van for a day.
Microfiber towels pack smaller and dry faster than regular bath towels, which matters when storage is limited and airflow is not guaranteed.
For showers, swimming, dish spills, and general camp cleanup, a dedicated quick-dry towel keeps wet fabric from taking over the vehicle.
The tradeoff is feel. Some people hate microfiber. If that is you, buy a better travel towel or accept the bulk of cotton.
The towel is boring. The mildew you avoid is not.