I really don't like the settlement building for reasons mentioned in this topic so far, but also because the construction interface is very ungainly.
I much rather wished if Bethesda had insisted on this mechanic that we could do it from a map/outside perspective than from the player's point of view.
And what was mentioned here, it doesn't lead to anything. Would it for example resulted in a new ending in which the player unites the Commonwealth and established a network of settlements that in time form their own government and civilization the effort put into the building of these settlements would have felt rewarding.
It is just there now.