The roads from Memphis to Mississippi are pretty rough so if you choose not to strap your boat down, get ready to watch your boat and trailer bounce all over the place. The best benefit that I see from strapping is that if you do hit a bump at 70mph, both your boat and trailer bounce together instead of seperately. This will keep your boat in place and not end up mis-aligned to one side.
I also have the LED lights so I never unplug as my brakes are also tied into the same point.
I think a lot of this will depend on the age of your specific boat and trailer type.
2011 Supra 21V
Wetsounds Icon8's
2012 Tundra SR5 Crewmax 4x4