If you were of nobility in the Middle Ages you would own a chair with welted cushion and it would have been exquisite. In the Spanish Court, only the honored were permitted to sit in chairs that featured elaborately decorated cushions with welting. And in France, the most privileged were permitted to kneel on a welted cushion behind the King in church.
We can definitely say that even to this day cushions with welting have not lost their function or their attraction. Cushions today are accessories as well as a seating comfort. Functionality, however, should not dictate the style of your pillow! Dress it up with welting.