I have yarded-in rope to catch leader falls too, but it usually seems more like about an arm's length, not the 3 meters or so discussed here. I guess I would be hesitant to suggest such a practice for people learning to belay (in this forum perhaps?) when there is enough to keep track of as is when you are starting out. On climbs that are at the leader's limit, a little slack seems nice to give you enough time to assure the leader is not fighting for rope at a desperate clip as they go out of view.
Matt, since you have been belaying leaders on hard climbs longer than I have been alive I certainly yield to experience.