Necklaces, earrings, pins, handbags and other accessories can be matched perfectly in color and fiber contents to the custom designed apparel. But there are some inherent problems in knotting. To form many of the knots the yarn undergoes harsh handling. Some of the designs of knot combinations require very stiff yarns or cords. Very round yarns show off the knots best.
Some knots are just too complex and maybe unsuitable to tie with handspun yarns.
As I investigate further, surely there will be more problems to solve.