My guess was that it took panoramic photos.

I've got a few very similar things that were donation gifts to the Audubon Society in the early 80s, except instead of a book they come with a stack of about 20 cards with photos and descriptions of different birds on them. The little flexidisc is glued to one end of each card and when you stick it in a slot in the machine it plays an example of that bird's song.

Got them NOS for $1 each in the mid 2000s.

I was expecting some Japanese niche fetish