> Why should apps have access to a user's SMS / RCS?
It could be an alternative SMS app like TextSecure. One of the best features of Android is that even built-in default applications like the keyboard, browser, launcher, etc can be replaced by alternative implementations.
It could also be a SMS backup application (which can also be used to transfer the whole SMS history to a new phone).
Or it could be something like KDE Connect making SMS notifications show up on the user's computer.
It could be an alternative SMS app like TextSecure. One of the best features of Android is that even built-in default applications like the keyboard, browser, launcher, etc can be replaced by alternative implementations.
It could also be a SMS backup application (which can also be used to transfer the whole SMS history to a new phone).
Or it could be something like KDE Connect making SMS notifications show up on the user's computer.