There's also a value in simple, very lightweight vehicles. I'm continually amazed by what I can do with my mostly-stock 33 year old, 60hp, Suzuki Samurai.
Yes very true, but my 75 horsepower had to drive something above 2500kg 4x4 camper
No one is arguing with you, but once you try front and rear selectable lockers you will be a convert. Mostly because you can do it all and tread lighter. 2WD needs momentum. 4WD needs wheel speed. All locked up lets you crawl and tread lightly. If you are basing your opinion on mud bogs and rock crawling, you won't understand. If you wheel in an ultralight you do understand and when you have selectable lockers, front and rear, you'll be WOW.
Yes of course it is an upgrade, and it will do nicely.
However, talking about what a necessity is, no I believe it is not.
Because people are spending thousands of dollars on there cars, which in fact itself is holding them back from travelling. Because they have to work more.
My opinion is that you have to get to know the vehicle. There is no point in modifying a vehicle if you don't know what the limits are.
If you really get to know the vehicle, most people who are new to 4x4 will already be surprised what you can do with it. And will likely not take it to the edge of what the car can do.
A standard 4x4 gets you to so many awesome places in the world. A lot of time people are just making it worse, which includes overloading vehicles. But also the modifications can cause some side effects.
As for my own modifications. I am only really happy with the small lift that I gave it, because the ground clearance was really low. Anything after that was mostly pointless.