My old Starcraft did not have a bilge pump went I got her and that's the way the factory made her. I added a pump and separate float switch. The float switch is wired to battery so it's always in auto mode. The dash switch is wired to override the float switch.
The reason I did it this way is the be able to replace the pump or float switch if either goes bad. The pump is still working fine, but the float switch failed and has been replaced.
I don't like pumps with an internal float switch, a water sensing circuit or timed operation. When either the pump or auto on parts fail, you have to replace the whole shebang. I prefer to have two parts, not one, for ease and cost of repair.