You might not consciously observe how your light switch transitions to the opposite position, but I’d argue that most people still have an immediate and intuitive understanding of how both end-states of a light switch are related to them applying physical force onto the switch.

The toggle transition is supposed to resemble this notion, and aims to allow the user to build up an analogous mental model of cause and effect.

To me, this sounds like a valid and worthwhile idea in general. That animations are not always appropriate or fitting, or that they sometimes are laggy and sluggish, is a different story.