I wear ankle weights.
It helps my trim. My SAC rate is excellent, I think that IF there were studies done on air consumption with and without ankle weights on a 'normal' dive, there wouldn't be much difference.
Everyone has an opinion about ankle weights (and everything else) do what is best for you and trims you out best.
My BC weights are around my waist, not my hips where the center of gravity should be. Ankle weights help me to compensate for this shift of gravity and puts it back to where it should be.
Again, this works for ME, do a buoyancy check to get to your ideal weight (most divers are over-weighted) and borrow someones ankle weights (don't forget to remove the equal amount of weight from your BC) and try a few dives with them. You may hate them, you may like them but you won't know until you try it.