Rotation is extremely important, imo. Especially when staggered + rwd/fwd.
For example, if your right side + rear wears faster, such as if you're lapping a CCW or a road which has more left handers in a rwd car, then you're buying one individual tire each time as every tire is wearing at a different rate, meaning eventually all your corners will have different grip levels (varying heat cycles, tire life, compound life) and you'll be spending more time at the tire shop.
Results in a less consistent car and more waste of time.