The slower you retrieve the closer the fly becomes to being right under the indicator. This can be a positive if you are fishing for crappie or gills close to cover. You can hold your fly quite close to the brush and twitch now and then until the fish takes the fly or Mr Bass comes along and hits your indicator or fly. I have caught quite a few crappie this way.
For an indicator I now use home made poppers, some quite large and have had bass hit poppers with a diameter of 3/4 of an inch.
Tim