The many stitches in black thread on the lapels have the function of imparting a graceful roll to the lapels. Without these hundreds of handstitches, the lapels would be loose and floppy, as opposed to having a sculptured roll. The pad stitching is very traditional to the tailored jacket, but completely absent in most lower grade tailored jackets and from RTW jackets.
Here you see one of my coatmakers pad stitching a lapel by hand. The lapel is intentionally kept in a rolled state as the stitching is done.