I agree that decorative stitches add a lot to quilting the tops. A border that looks too wide can have a better look when a decorative stitch is added, usually closer to the interior (than the binding) of the quilt top.
You can highlight certain blocks (think about alternate blocks) or the center (or alternate borders) of medallion style quilts.
I agree that stitching out the decorative stitches on to reference strips or pages does increase your creativity and frequency in using them.
Having a few (or many!) decorative threads in multiple weights opens Pandora's Box to the decorative stitch library you may have. Don't forget that many utility stitches lend themselves well to decorative uses also.
The serpentine stitch (a regular wavy line) is a favorite for allover striped, diagonal or grid quilting - it adds attractive texture as well as locking the fabrics together.
Decorative threads have become another 'stash' to use with the 'stash' of decorative stitches,lol.