Paperless bathrooms exist in various parts of the world. The folks there use water to wash which is more cleaner.
How do they dry off?
Mostly the areas are very varm already. When I backpacked around South-East Asia I got used to this, we called them bum guns. After you're sure you're clean you can just shake it off and it'll evaporate very fast. Although most places had paper you'd use.
The Toto Washlet S300e comes with an air dry feature.