No you don't. You want such a capability. But how often do you use it? Isn't this like buying a 20,000-sq.ft. house for when the extended family visits? Or a Cray supercomputer just in case you have to break Russia's codes some day?
And 2 of those people won't be comfortable -- the third seat in those models is not, especially being over the solid rear axle.
Heck, why not a Nissan Armada if you need that capability? 9100 lbs towing, only 6 inches longer. Or Toyota Sequoia -- 9500 lbs towing, only 5 inches longer. Both have more comfortable third seats.