Convenience
You can listen while you drive, work-out, walk the dog, whatever fits into your life.
I've often wished for audio files of the adventure modules or rulebooks of new games I am learning. It would be extremely convenient when driving/traveling or winding down for the night in bed. So, Thank you and I hope there is more to come!
I've been bugging publishers to do this very thing for years! Very affordable as well.
As a totally blind gamer, I just want to say how much I appreciate your doing this. True, I have access to the PDF through my screen reader, but having a human voice reading the book will make it much easier to digest the information.