Mountaineering Rope's sole use is to provide the player a way to climb up sheer cliff faces. The player can find a suitable outcropping, then place the rope to allow for a descent. Once the rope is in place, the player can also use it for an ascent, although this takes up much more stamina.
Several ropes are already placed, particularly in Timberwolf Mountain. This ropes can be moved if the player wishes.