It enables you to get really, really stuck farther from civilization.
When you finally 'break loose' on ice, you are really in trouble.
D@mned things tip over far too easily (8^D).
(Note, these are older models, with buckboard hard suspensions and manual transmissions/transfer cases, not the computerized rides of today).
Used properly, yes, they are a great tool, but they are not the invincible conquerors of the off-road many fantasize about.
Nor are the the laws of physics defiers that their driver think they are on freeways. I dread winter when monstrous 4WD vehicles driven by clueless people fly by me on icy or snowy roads since everyone thinks that 4WD prevents all skidding and makes vehicles stop just as well as they do on a dry road. Don't they notice vehicles just like theirs in ditches and wonder why they are there?