Yeah, until Facebook quietly changes how that works and gives all sorts of new permissions to apps you've already authorized with.

That's the real problem here: Facebook has a history of wanting to expose as much personal information as possible, including exposing information that was previously not exposed without warning. I don't necessarily distrust the OP's business today, nor do I necessarily disagree with the permission settings I can set today. What I don't trust is Facebook's future changes to those permission settings, nor what the OP's business is going to do when/if it has more access to my information than it used to have.