Document level locking improves security?

I just read this 

Chief among them is document-level locking, a feature that will enable developers to enact security on individual database documents rather than at less-granular levels. -  http://sdtimes.com/mongodb-2-8-features-detailed/#sthash.Vk0SCyLu.dpuf

Did I miss something? Does document level locking improve the abilities of security? If so, how?

I don't think the author is talking about security as in securing your data, I think they are using the term "security" as in "to feel secure" about something.

To be honest that paragraph doesn't make much sense to me as is anyway.

Hehehe...ok. If it doesn't make much sense to you either, then I feel better. I read it myself and was like, "Holy cow! Did I miss something important here?".