I would say that goes for most of the hand stitching, like your handrolled edges on a pocket square or a hand-stitched lapel buttonhole. They're things that one may or may not appreciate but they don't add any functionality, simply aesthetics.
On the other hand, having hand attached collars and sleeveheads, for example, do add something. The tailors are able to shape those round areas better, including the extra material / shirring, so that it will feel better than one that is attached by machine. It takes extra time (and therefore cost) but it has utility. Of course, they almost always reinforce the seams afterwards with machine stitch to ensure a solid construction - but the hand-stitching still shows and is something one can appreciate as a mark of fine craftsmanship.
It is quite impressive to see these people work - we visited both Mazzarelli and Inglese workshops in southern Italy and saw them work. It's quite inspiring and makes you want to give these guys more work so they can keep the craft and skilled manpower going.