Your refrigerator, water heater, thermostat, heater, Air Cond. CO and LP detector all work off of 12v. Taking the battery out would make all of those system dependent on the Converter/charger alone. As rvjimmy
said, it puts extra work on the converter and leaves you no backup if the converter or shore power goes out. All the above systems would shut down without notice. Not a good idea, especially in the case of the CO and LP detectors. With no power to the LP detector, it shuts of the gas so you can't even light a burner without 12v power in the camper.