12.2. If you do not maintain a backup of your Account data outside of the Services, you will be may not be able to access STEEM, Steem Dollars and Steem Power associated with any Account maintained in your Account if we discontinue or deprecate the Services.

I'm quite confused about what they're trying to say here. Is there any account data stored on Steemit and only there that we need to back up (how?) in order to keep our blockchain account functioning in the eventuality of Steemit site being discontinued? I was under the impression our Private keys is all we needed. Is that false?