For your consideration regarding purchasing a 2x4 vs 4x4, driving in 4 wheel drive is useful in a lot more circumstances above and beyond the times that it's absolutely necessary. On washboard roads, using 4wheel drive keeps the rear from sliding around. And, even in mild forest service roads and trails, it keeps you from losing traction in the first place or allows you to more quickly regain traction when you lose it. And most importantly, on the same washboard roads and trails, it is far less damaging to the road surface because it keeps hopping, sliding, and all the traction/force spread out over more contact patches and more road surface compared to being in 2 wheel drive. Washboard roads would be much less washboard if everyone used 4x4 on them.
And, as mentioned by others, 4lo is very useful in trail driving as well because it gears you down much lower than 1st gear on high range. It allows you to drive uphill slowly, over steep or loose terrain, compared to 4hi or 2hi. Keeps your speed slow to get over ledges and not risk braking parts because you had to "use momentum" to get over terrain. More importantly, it allows you to control your slow-speed descents with engine braking rather than dragging your brakes for miles at a time. There are days we are driving down a forest service road for 5 - 10 miles and only touch the brakes a handful if times the entire way out. Slow, 4lo-descents are reason enough to get a 4x4 in my opinion.