FWIW, I definitely started faster speeds with audio books. Figured it was kinda like speed reading, also it seemed like the best way to get through a bunch of stuff, when you don't know of its worth your time or not. But I have noticed I retain more when I listen at normal speeds.
#40hpw
https://fountain.fm/episode/G8YZMq5ImH5H98L3BMuy
#40hpw
https://fountain.fm/episode/G8YZMq5ImH5H98L3BMuy