Son had a player on his college team (high academic "public ivy", mid-major D1) that took a PG year. I wish I knew all the circumstances because he was a good player (got drafted after his senior year of college, which meant that he was 2-6 years older than most in his draft class). My guess is that he may not have been recruited much out of HS, and the family had the resources for him to go to a wonderful school for PG year.
I heard a new (to me) term recently.....taking a "glide" year between college and graduate/medical/other school. Friend's son is going to do that before medical school while he pursues some wonderful research project for a year.