I have a Jeep and towed with it or a predecessor for 7 years. It that time I only used the 4 wheel drive a few times. Once for a rising creek, a few times for loose gravel hills in campgrounds and once for snow. In all those cases I probably could have gone through without 4X4 use.
4X4 capability adds cost, weight and reduces mileage.
Your real questions should be:
Will I need the 4X4 to go where I want to go.
Will a 4X2 have adequate towing capacity to haul my RV.
Are the cost to buy, maintain and fuel efficiency worth the it.
2017 SLX 195RB
2014 Jeep Grand Cherokee Overland, gas 3.7 V6
Andersen WDH hitch
Dometic Milenco Aero mirrors