One of my pet RV peeves. We were weekend boaters. There are no water spigots, no anchorage bathrooms, power pedestals on the water. If you are out for more than a daytrip battery power & fresh water capacity is king.
Dry camping is just like anchoring out. Our 32' boat has a 115gal freshwater capacity. Needed it for a family of 4 out for 2 nights. Our 5er has a capacity of 100gal. We breeze through 5 or 6 days dry camping no problem without being stingy on the water use.
When we were trailer searching if it did not have a minimum of an 80gal freshwater tank, it was cut from the herd of possibles. That requirement alone narrowed the choices down in no time.
It doesn't take anything to haul around a big empty tank. It sure is inconvenient not having the capacity when you need it.