Actually this lets you do more than what iTunes lets you. iOS 8.3 has already prevented tools like iFunBox (which also uses this IIRC) to access the app sandbox directory.
Backup is done via a completely separate service.
iOS releases do tend to arbitrarily change the security policy of these services, but it's not clear that "Rootless" is anything more than business as usual. Guess we'll find out Monday.