Hi Michael,
the "bleeding off" is certainly academic/legal, and a prerequisite for landing-distance-calculations to be legal. The shorter the landing distance in the book, the better the plane sells. So it is advantageous to calculate touchdown with "Vref" instead of the minimum Vtgt of Vref+5.
If you are approaching in high (and usually gusty) winds, it would require you to pretty much retard the thrust levers to idle when crossing the threshhold to bleed off 15kts of speed additional until touchdown. A recipe for disaster, as there would be no instantaneous power available in case of a sudden drop-shear or required go-around (spool times). And usually landing distance is not a factor for the 737, especially not in situations with strong headwinds.
If you approach with a solid speed additional, you will need to fly the plane onto the runway, taking care not to bump the nosewheel first (usually you will fly with Flaps30 to give you a better controllability, anyway (higher speed -> better control, less driftangle). Chop the thrust levers at touchdown.
Jan