The MLK example is a great one. Also, it's still not 100% clear what happened with Hendrix, Marilyn Monroe or the Kennedys. I read recently that there was evidence of the NSA having dirt on a governor, which was used to blackmail him (can't recall the specific instance unfortunately). And of course, I'm sure everyone knows about what happened with the IRS and certain non profits last year, while not directly tied to the NSA gives an example of why this stuff matters.

So yea, it's not to protect people like us. It's to protect the MLKs, the politicians, the accountants, the journalist, the news anchor, etc... Everyone either has a skeleton in their closet or cares about someone who does. If one is so inclined, having this information can be extremely valuable when trying to prevent a "free society" from becoming a little too free.