And it may have been the only way to satisfy the court anyway, they had previously assured the court surrounding communications to these wouldn't be searched, and then they were searching them too (so even if you didn't mention a targeted email, if your email was in an internal email provider bundle (like a backup across data centers), it was getting searched too:
>But last year, officials said, the N.S.A. discovered that analysts were querying the bundled messages in a way that did not comply with those rules. The agency brought the matter to the court’s attention, resulting in a delay in reauthorizing the broader warrantless surveillance program until the agency proposed ceasing this collection practice.