Most timber kit house walls are 140mm timbers at 600mm centres, covered with OSB, a layer of Tyvek, then either timber clad on the external skin or a cavity and brick/block/stone on the outside so its not just the cheap stuff that's got OSB on the outside. Between the 140mm timbers they can fit a good amount of insulation, cover it on the inside with a vapour barrier then plasterboard the inside.
Not a fan of it as a roofing material admittedly but I don't have any problems whatsoever with it being used in the way I just described.