Player movement

Background scrolling is not "player movement" - it is more like a side-effect of player movement. Or, if by "background scrolling" you mean moving all of the objects in the level, while always keeping the player at a fixed position, then performance-wise, this is a terrible idea compared to just changing the player position - it's just a huge waste of CPU cycles (or like trying to move the whole planet Earth under your feet to get from one point to another, because you're too lazy to walk :) ).