Around here (semi-rural WI, US) it's not so much the terrain where you're going as what you need to haul. 4'x8' sheets of building materials are one that get me a lot; I recently had to cut a sheet of styrofoam in half in the parking lot of the home improvement store to get it to fit into my car. There's also pieces of equipment that won't fit in the trunk (boot), like lawn aerators, rototillers, sod cutters, and stump grinders. (They might fit in a van or CUV, but then you have to deal with gas fumes and dirtying/damaging the interior.) Dirt and compost could fit but would be a pain even with a tarp.

I see a lot of fashion trucks but most of them also get used for towing or hauling on the weekend, and a lot of that stuff wouldn't fit in a car and would be unsafe on a trailer. A lot of people around here also have motorboats that would be too big to safely pull with a car.