I imagine the 'thread' you are using for embroidery is a bit different than the 'thread' the rest of us are talking about using for appliques and bindings. Embroidery thread is usually a bit thicker so you can actually see the stitches. For sewing it is designed to virtually become invisible.
As an infrequent appliquer, I love silk thread because it hides a multitude of my sins and blends well with the colors of the appliques, allowing me to keep just a few colors of thread on hand.
I have worked with silk embroidery thread and it makes me feel so classy when I'm using it!
Jan in VA