Roof-covers or canopies for caravans are used almost exclusively for permanent camping or with static caravans.
The mobile cottage then heats up less. At the same time the caravan will be protected from heat, rain, hail, snow and ice. Caravans with a canopy are often used for more than 30 years at the same site.
For motorhomes and campers there are the Van-protect-roof, which is usually mounted as weather protection only in winter.