Just curious, how could this be used? I assume one could broadcast over the chat addon channel without others being able to look into the conversation or something, but in any case, it's some neat coding you've done.
Its primary purpose is to provide a way to release addon updates/content without the need for users to re-download the addon.
For example with bigwigs and deadly boss mods, new boss timers can be published in-game by the developer to friends/party/raid/chat channel, anyone who receives the update can validate that it is actually from the developer and that is hasn't been changed, then forward to more people who can do the same.
It's also secure enough to allow pure LUA code to be signed, broadcast and used, to provide core upgrades as well as content updates.