Well said. Was it Napoleon who said "Any fortress can be breached with enough money and time?"
I build the walls mainly just for the fun of building and making it look real. But even if they do spawn inside, it restricts movement, and I place my internal turrets with this in mind.
Anything spawns inside my walls, they are going to be eating a LOT of hot lead, even if my settlers have no weapons (which says nothing about the aggravating "damage everything script" [as it has been called] that evidently runs when it gets attacked and you ignore it).
I so far have not bothered to outfit settlers with better gear. Hasn't seemed to matter, and I wanted to make them as uniform as possible. With something like 10 settlements with >=15 Pop, even with the gigantic pile of gear I've hoarded I probably couldn't outfit everyone.
I do like to put the Doctors into lab coats, the traders into trader looking garb, the clothing dealers into a nice clean fancy outfit, weapons and armor dealers dressed accordingly. I seem to find enough "T-shirt and jeans" that outfitting all of my bartenders with those is an option.
Dang I wish the vendor sold more of the more mundane clothing items. I'm tempted to just spawn myself in 40 or 50 "Padded Denim Jackets" so all my farm hands are dressed the same. I suppose the syntax and keywords for that would be pretty much the same as in Skyrim, eh?