Currently, it only backs up the addresses you have already created.
In future, it will have BIP32 deterministic wallets. You only need to backup the once, immediately after starting the app for the first time.
That's a shame. I don't like reusing addresses (I.E. change back to the same address, or, multiple payments) for the sake of it being hard for me to manage what payments are what (One address/payment is a lot easier), so, this wallet is unusable for me at it's current state. Hopefully when you come out with this feature it'll be usable. Is there at ETA (Time/version)? Or, is it just in limbo currently?