Your call Moffy - no right or wrong just advantages/disadvantages. Having it switched means you can easily reset it if you have the misfortune of encountering a software glitch. Not having it switched you can still do it - you just have to shut the entire boat down. Some networks are dual powered with things like gauges taking power from the engine harness and other things like GPS antennas being powered either through the master or an on dash power source. Many and varied ways of doing this.