Imagine this scenario:
You're the Lone Wanderer. (Forget that "survivor" crap - that name doesn't nearly do you justice. But I digress.) *** Clears throat. ***
You're the Lone Wanderer. And while you're wandering, alone, you come upon an area that makes for a tempting base or settlement. As you stand there with the radioactive winds blowing on your face, the bodies of dead radroaches, mutant dogs and that really strange deer-looking thing at your feet, you can see in your mind's eye the buildings and towers, and their placement. There are resources. That boxcar and those cars and several trees. A well could go there. Maybe a bit of garden.
The only problem is Bethesda, in their wisdom, missed this spot! Geeze!
Wouldn't it be cool to clear (almost) any area - and then build a settlement? Last night I came across an area and I thought: "Wow, I wish I could move sanctuary here."