I agree it's odd that they're actually marketting it as anti-law enforcement.
There are certainly other reasons to appreciate secure encryption though. But "not even a disgruntled apple employee, or one paid by your business competitor" brings up questions that are not good marketting to put in people's heads. Even "not even a hacker, cause we used actual secure crypto" is not what they want people to think about.
Now, personally, I include "not even law enforcement" in my list of attackers I'd like to defend from, and there's nothing wrong with that (and there's not supposed to be in America, the 4th ammendment and all). But the fact that it's actually good marketting generally (or at least they're betting on it) -- well, we have Snowden to thank for that. And I doubt it will last.
Also, of course, there are a variety of reasons the iphone crypto as a system isn't all that secure -- including but not limiting to the fact that we still have trust apple (we can't see the code, or the code in the updates pushed out regularly).
Not that I disagree that it's a benefit to make it harder for law enforcement