This is all presumably to drive a little more thickness of out of the MacBook
Another casualty in Apple’s ruthless quest for thinness is the trackpad’s clicking mechanism.
Looking at teardown comparisons between the old and new MacBook, it seems that the thicknesses of the two trackpad units are hardly different - the new one may even be thicker! Additionally, the old trackpad looks mechanically simpler - space savings don’t usually ride in on the backs of more large components. I think this is a testbed for a technology that Apple wants to make much more use of in the future — it’s not a space saving objective.