There are several ledges along the slope which can only be reached by sliding down from a higher point on the slope. One of these ledges leads to the Machina Refuge.
The slope is too steep to walk up, and an uncontrolled slide down the slope will cause the party to overshoot the ledges and hit bottom at a fatal velocity. However, running or jumping directly uphill while sliding can reduce the character's speed enough to stop on one of the ledges and survive a landing. Due to a quirk in the game's physics, it is also possible to go up the slope by repeatedly jumping uphill.