Why let them land, why let them take-off??? The side-stick and rudder pedals on the right also costs a lot of money!!!
When I give IOE at an airline to an upgraded F/O that does not let the F/O's taxi, it really shows and it takes time to get a good feeling taxiing and be smooth.
Also, very rare; but have you heard of tiller failure or Pilot incapacitation?
Btw, it is standard equipment on all Airbus FBW, NOT an option.
Look at the reasoning on olepilot's post, makes sense!!!
G