In another life I was a mailman using a bike.
To do that efficiently you steer the bike with one hand, keep the mail on a tray in front of the bike and deliver it with the other hand as you keep biking.
When I was doing a new area I needed to bring a map to know what way to go.
Having that map be interactive and visual would have been a real benefit to me - it was an A4 sheet that I needed to stop the bike to read. Audio wouldnt have been as good, as I was veering, slowing down and accelerating a lot so the directions would have been confusing. It's a situation where something strapped to my arm would have been a lot more effective - a paper map was too small to strap to the arm, but an interactive map would have been perfect.
Google glass, or a flexible screen would have both solved that situation for me.