The first advantage of a remote panel is that is is a more convenient way to tun the inverter charger on and off, particularly if it is located in an inaccessible location.The other advantage is that you can adjust the charge current on the fly. For example if you plug in to a 15 amp outlet you might blow the circuit breaker on the power supply. With the remote panel you can dial down the amount used for charging. The most common remote panel used is the Victron Energy DMC000200010 Multi Control GX for Multi-Plus and Quattro which also happens to be the cheapest.