The Shakers used tapered legs on tables whenever possible. The main advantage of tapering is reduced weight. It was important to the Shakers that furniture be light enough to be moved out of the way when not in use.
Turning, like tapering, is another great way to reduce mass while still leaving enough material for structural integrity. Turned legs, stretchers and spindles were also easy to replicate. Actually, most turned parts were often tapered also, like the base of the candle stand in this photo.
Rockers in the Shaker Village at Pleasant Hill via Wikimedia