Several say use the switched supply but do not say why they would do that. Interested if I'm missing something. The only advantage I see is you will not forget and leave the GPS on which would run down the bike battery after a day or so. I agree that is important but I have no problem turning it off when I put the bike to bed at the end of the day or end of a ride. Advantages exist for leaving the unit powered up for a complete ride even when stopping for gas or lunch.
I have a Garmon Neuvi that I plug into the switched power port ( cig lighter). Once you turn the ignition off it gives you an on screen prompt. If you chose to ignore it, it shuts off. I can remove it and when I put it back in serves, turn on the bike, it starts by its self. On occasion when gassing up I’ll turn the key to acc. We stop in a lot of smaller towns to eat and I’m not willing to tempt the locals. I have in the past have forgotten to turn dome lights off in the car and had to jump start it. If your a low mileage rider you very well my find your self with a dead battery when you really want/ need some wind therapy.