I own a 2015 179 and a 2007 Ford F-150. I drove from CA to MO to pick it up in February. On the trip back, I kept it 2WD until I hit snow on the freeway. I then dropped it in and out of 2WD/4WD depending on how serious the snow was. And, there were a couple of times when 4WD was a true blessing....
(1) Heavy new snow on freeway in New Mexico caused slipping of truck and trailer when switching between lanes of freeway because I had to "jump" from one set of tire tracks in the snow to a different set of tire tracks in the other lane.
(2) When at a stop on a freeway off-ramp that was uphill with fresh snow on the ground, truck lost traction when light turned green. Switched to 4Low, and was able to get out of that pickle. Full sized 2WD truck in right lane next to me struggled and slid back a bit.
All that without chains....
Having said that, and looking back at my poor decision to drive across country in February, I don't know if my next vehicle would need 4WD, because I've learned my lesson.... no more winter snow driving for me with trailer.
However, at the risk of sounding macabre, another scenario comes to mind where 4WD could save me. What if the trailer blew a tire on one of the many steep switchbacks heading up to Kings Canyon National Forest? Trailer could start to swing over the side, pulling truck with it. God forbid that were to happen, but it might be nice to quickly flick to 4WD. Sorry fellow R-Podders, sometimes I think perhaps a bit too much about "worst case."