Someone who's an occasional baker might not use it, but it's as common as muck - my dinky local Kroger carries at least three brands of bread flour (Pillsbury, Gold Medal, King Arthur), and probably a couple of other brands that I normally don't notice.Sorry - I know people do use bread flour in the USA but my possibly mistaken understanding was that a lot of people don't and maybe its not so easily available in supermarkets? I do see a lot of US recipes that use AP.