Multiple Apps are ruining at the same time.
They are selling the book in a DRM form precisely so they can split the reading rights from the voice rights.
No. They are selling information in a medium and trying to prevent you to use another medium to use the information you've already payed for.
So no, they don't have a point.
"Take that, you hostile sons-of-bitches!" -- James Coburn, in the finale of _The_President's_Analyst_