I'll say I use 4WD and 4LO often just to gain better control than I'd get in 2WD. But the point is I don't use 4WD to get farther down a muddy trail. Or a snowed in trail. Mud, Snow, Sand, I deliberately use 2WD for the confidence I will be able to back out in 4WD.I dont know myself (not enough experience) but I dont think I would drive in 2wd on sketchy trails if I had 4wd available to me.
4WD, 4LO let you tread lightly rather than reliying on wheel spin and momentum in sketchy situations. Crawling in 4LO is a great place to preserve machinery.