@Watson love it. I did that for one I am working on now! Leftover bits + muslin are the backing on this WIP.
The other thing I’ve been trying to do is use up any tiny coordinated leftover bits into scrap blocks right away. instead of sorting the leftovers into their color family scrap piles, if I make a wall hanging, mug rug, bag, or even just a block that will become something someday right away, it’s already pre-coordinated colors and almost a lil mini version/reminder of the quilt itself.