surely keeping power on as long as possible will allow a much lower speed therefore a smoother touchdown and shorter ground run.
Yes, once you get the plane behind the power curve, you can start adding power to fly more slowly. However, getting to that point during approach is not as easy as it seems.
Many planes, in this configuration, will have the tail so low, that banging it on the ground is a risk. I've had a PA-28 stuck in ground effect, with nowhere to go doing this - it won't climb away, but lading back will result in a tail strike, and hard landing. It also requires very large control movements, which require great skill. Best avoided until skill is great....