Stepping from the surface of the platform to the surface of the wave provides proprioceptive input (input to joints, muscles) which helps orient the body to where it is at in space.  Walking up or down the wave will require core strength to maintain balance and keep from falling down.

This can be used during articulation drills! With every correct production they can move up/down the steps to get across the ramp the quickest. Parent could also use the sensory components as motivation for correct production of sounds.