Adding the breadboard option to your table is totally an aesthetic choice depending on your taste and style. Option available only on Farmhouse Tables and Harvest Tables.
Breadboards are not always flush with the sides of the table. Since wood moves across the grain seasonally (in warm weather the panel expands, in cold weather it shrinks) and not along the grain, a breadboard end will either fall short of the panel edge or will extend past it, depending on the season.
Adapted from Fine Wood Working, “All About Breadboard Ends”.