Why not just skip the polishing/paint correction step?
Not necessarily. The condition of the paintwork by itself, without a wax or sealant, makes up about 90-95% of how good (or bad) the paint looks. In other words, a wax or sealant is limited to how good it can look by the condition of the paint below it. So, the extra 5-10% in gloss, depth, wet-look, glow, or shine can be added by the last step of protection.
