Growing up the only option was treebooks so of course that is familiar.

I gotta say though, reading on my phone is nice. Turn on night mode for yellow light. Use the white text on black background to keep it dim. Plus my progress is saved and synced.

And you are right about that bedtime reading. I can read without disturbing the wife and that is huge. I wouldn't read nearly as much if I couldn't read on my phone.

I've been curious about audio books though. I've mostly used the bus for commuting but I'll be moving in a bit over a month and will be driving after that. Might be time to check them out.