I have heard that if you are entering a quilt into a show, you need to knot/bury your threads.
I am personally such a prolific quilter, it would actually help if the stitching came undone in 3-5yrs
so I have someone to give another quilt to. I do the locking stitches on anything not destined to go to a quilt show.
On garment sewing, you are taught to back stitch over the beginning and end of every seam you sew. Locking stitches do the same thing with quilts and should behave the same (ie not coming undone)