How can using split throttles help when landing twins in crosswinds?
The use of asymmetric thrust when landing a twin in a crosswind effectively accomplishes the same thing that rudder input does.  It induces a yawing moment about the aircraft’s vertical axis, the same as pushing on the rudder pedals does.  It helps to alleviate excess rudder pressure on the flight controls during the approach, making it a little more comfortable for the pilot to fly the approach. You are still required to apply aileron input into the wind in order to hold the runway centerline.   Using asymmetric thrust during a Crosswind Landing does not alleviate aileron pressure or required bank angle to track the runway centerline.