I'm asking how people can focus on two things at a time. I assume that an audiobook (or podcast) requires focus - otherwise are you really "getting it" or just getting a sense of it?
I can certainly understand during a commute (especially on public transport, or if most of your commute is a traffic jam) because the level of conscious attention required on the non-listening task is close to zero.
I admit to listening to music while doing other stuff - but I'm not focusing on the music. It's just a soundtrack - no need to remember plot lines, or make sure I don't miss critical story elements.