Dozerman, since the suspended undercarriages "conform" to the pavement when you curl out the bucket and use it for downforce a larger percentage of the track is still on the ground. Suspended undercarriages flex, so when you push up the front and transfer the the weight to the back, the undercarriages flexes with the move, therefore it keeps the tracks on the ground. With a rigid undercarriage, the rear idler acts as pivot point which in turn lifts the front of the undercarriage off the ground.
Plus Cat and ASV have wider tracks with lower PSI which is helpful in snow. When travelling over snow and ice, think of it like truck tires. Would you rather have a skinny rail tire or a wider, flotation tire? The choice is easily made. Traction is achieved over slippery surfaces through ground contact area and Cat undercarriages would clearly have the advantage over non-suspended carriages in snow.
Go hard, go fast, or go home