Yes I understood your question the first time, while it is true the front legs may or may not have the turned column detail, most do not, it is also supported the full length across the back edge, thus very rigid. The columns on the four corners provide the overall rigidity and looks better than just a four sided tapered column, making it a differentiator when trying to sell the patter to establish trend.. Take a look at the top view of the previous drawing in the blog from Chippendale's"Director" book and you will see the tenons that support the corners for the column. What I don't know yet is if that is the same for the bottom and I expect it is, it would be super stiff, with relative minimal build time, no large bits to decoratively carve, and out of place for a mechanical table to be used for serious "thought use" by the user of the table.
Or of course I could be completely wrong, for without written "intent" to go by one does not know the designers mind unless approached from a technical mechanical engineering viewpoint.