My guess is that the toy in the Twitter thread was the result of a kind of refactor. If you find a recording of the original it has a traditional music box inside which actually plays the songs (you can hear the tinny sound of the metal tines). So they probably took the original, figured out how it worked, replaced the audio generation with speakers and the microcontroller and changed the read head. Since the newer ones apparently use a switch and no spring, that was an intermediate step to the current incarnation.
The first version was an electronic imitation (complete with winding) of the original. Once the winding was rendered unnecessary, you get the current version without that imitation and it loses the tactile component.
The original didn’t have a music box in the base; there was a spring motor to turn the record, but the actual music-box part was in the head (running along the record, which had detents in the plastic to pull the tines for the notes)—this is why you could get different songs by changing the disc.
This music box in the base of the new model is probably simply the cheapest way to get a spring motor for the turntable these days, rather than custom-manufacturing one that matches the original.
I wonder if the original revamp had planned to have it just be a wind up music box and only play one song.