I guess my only real reason was because I'm lazy...
What I wanted was the convenience (or the simplicity) of flipping one switch that would control both the tank selection as well as the sending units. Yes, both of my aux tanks have sending units. I have the valve on the floor as well as this switch on the dash that selects the proper sending unit. The green switch controls the cruise control and has nothing to do with the fuel tanks. Just gauging the thoughts of those who certainly have more experience on the matter than I do. Thanks for the input!