I'll second what Bill said. Never drive a regular 4x4 with all 4 wheels on a dry nonslip surface like asphalt or concrete. But there are a few fancy new all wheel drive systems out there now that are designed to be engaged full time. So we're not sure what your salesman is driving or maybe he's never owned a 4x4 or pulled a trailer...
As for the need for a 4x4 tow vehicle, a well kept secret is that the best places to camp aren't concrete pads at the end of paved roads.
And sometimes you need the 4x4 after you've unhitched and are exploring.