Just Habit
Its not a crankshaft thing...Its not really a prop thing...even though in years past it might have been with me......
Its just habit......For me at least....I usually don't have a very good steerable tail wheel so it almost useless trying to drive back.....
But Yes as Tony says this is really RC as in you can have control on the ground....I don't place much priority on being able to taxi my model.....my opinion is who cares if you can taxi this isn't like its an RC car.....My fun is when its in the air......
Now in competition flights your caller or helper goes and picks up the model...Taxi time is wasted time in the event...So you don't taxi and there is no reason to keep it running after it touches down......
Troy