Mike shops at Amazon, and has noticed a change in permissions that would allow Amazon to send him text messages. Leo says the cool thing about the Android system is that they would show him what permissions are enabled and which ones an app takes advantage of. So at least he'd know going in what they want.
Leo believes this SMS permission paves the way for second factor authentication, should he forget his password. Also, sending a text and reading a text require the same permission. So Leo says it's not really an issue to worry about. But it's good that Mike took the time to read up on it, rather than just hit "accept."