I've used silk ties, the biggest problem is there is no stability. when you cut a 2" square of quilting cotton you have a 2" square to sew with. A 2" square of silk ends up with having no shape at all
It is a popular fabric for crazy quilting projects, but over time those silks have shattered quite a bit. might be the fabric, might have been the dyes.
silk is also murder on rotary cutters and the fine threads embed in cutting mats so use an old mat is a suggestion.