We need to remember....
Trim is a function of Airspeed and not attitude.
Therefore if you fly an approach in a cessna 172 at say 70 knts and do not change the trim from say the trimmed state speed which is of course 70knts then ssais 172 will gladly stick 2 fingers up at you as it floats 1/2 way down the runway.
A good landing comes from a good approach, in any airplane you have a Vapp and Vref approach at one speed, touch down at another.
I teach accurate speed control down finals and at the height of a double decker bus - Pitch Up - Retrim to the revised speed of eith er 60 or 65 knots and the airplane will then dissipate energy and give a cushioned touchdown on the runway.
Energy is a function of Airspeed squared.
Try and land at 70 knots = 4900 units of energy
Try and land at 60 knots = 3600 units of energy
a 25% decrease in energy for a 10 knot speed reduction.....
Hey presto ace QFI landing every time.
The trim wheel helps maintain the correct selected speed