Besides the obvious benefits of OSM, I want to mention two benefits that may be useful for technologically savvy security practitioners.
First, it's possible to use OSM map data to create maps you can upload to Garmin GPS receivers. Check out this link for a list of maps that have already been converted as well as instructions for making your own maps.
Second, there is an affiliated project called Walking Papers. This Web site started out as quick and easy way to create printed maps that use OSM data. It's recently expanded its functionality and offers a simple way for people to add updated information to the OSM database. It works like this. You print a map then hand draw in detailed features. Once you've finished your enhanced map, scan the map, save it as a JPG file and upload it to the Walking Papers site. Your scanned map appears and you can use a simple, drag-and-drop editor to add roads and points of interest that will become part of the OSM database; which everyone will have access to. It's slick, and recently I've seen UNHCR-related data starting to appear on Africa maps thanks to Walking Papers.