It might be nice idea to see that someone accepted my friend invite, but why would I want to get notification that I accepted the invite? I already know that, how I could miss that I just accepted someone?
It is a small thing, but it just adds spam to that notification list/inbox.
Would be also great to skip notifications if someone accepted your invite while he was in this same room, but that would be probably more work. So just skipping notifications for accepted requests by yourself would be great