Gasoline generators are notoriously noisy (some are more quiet) and smelly. Many areas like US national parks have restrictions on the use of generators. Fuel cells are used in many space applications, they are perceived as clean and quiet.
Generators can cost upwards of a few thousand dollars, clean and quiet having value. If I had a budget of $10,000 (US) , could I purchase a fuel cell that would be appropriate for powering a RV/Camper/Trailer?
Why not solar?
Solar cells don't work well on cloudy days and under tree cover, Most (not all) campsites in the US that are primitive (without amenities like power) are under the heavy cover of an established forest.