Unfortunately, Differential Privacy proofs can be used to justify applications which turn out to leak privacy when the proofs are shown to be incorrect after the fact, when the data is already out there and the damage already done.
Nevertheless, it is instructive just to see how perilously few queries can be answered before compromise occurs — putting the lie to the irresponsible idea of "anonymization".
If nothing else, I appreciate the Differential Privacy effort, if only to show the problem space is wicked hard.
I worked in medical records and protecting voter privacy. There's a lot of wishful thinking leading to unsafe practices. Having better models to describe what's what would be nice.