As the moderator for a forum of Kindle users, I would say it's a good idea, based on the questions I've had to answer in the past about images, footnotes, notes, etc. People don't always understand how to look at them and then get back to the main book. It shouldn't take up much space. I can't see a down side to including the information. And I can see people getting frustrated and returning the books or giving them negative reviews for usability.
Betsy
Betsy