Many of us have seen smocking mostly on children’s clothes of a certain era. As a small child, I had a couple dresses that looked just about like the above illustration. It’s easy to see why it was so popular for little children of both genders. It’s attractive but launders reasonably well, and it obviates the need for fussy closures on small, squirmy children.
But when smocking started out, it was worn as much by adults as by children, specifically by adult male laborers. More fanciful stitch work on finer fabrics would be worn by wealthy people on their linens, as in this detail of a sixteenth century painting by Ambrosius Holbein: