I think it's more navigational? like I know "oh, I'd cross three streets and then be at the house" roughly, more than thinking about distance. It kinda equals effort to walk there and how often you'll stop for traffic more.
This right here. Nobody is converting the local average distance between streets in their heads into ordinary units of length and then converting. In ordinary conversation, to say "so-and-so is three blocks away" means you'd need to cross three streets to get there.
And just like you have an idea of how big a mile or kilometer is without having to get out a tool to measure it, blocks tend to be pretty consistent within a given town or city, so "a block" has a similar rough intuitive distance.
