If your quilt top is mainly comprised of dark fabrics, you may wish to use a dark batting. If any bearding occurs (batting fibres coming up through the quilt top), it will be less noticeable. For my kaleidoscope quilt, not only did I use dark batting but I also put a layer of batiste either side of the batting. This helped prevent any bearding. As I had a couple of light patches in the quilt top, I didn’t want the dark batting highlighting the seam allowance under those patches so it helped here too.
Those extra layers give the quilt a very nice feel and in my case, made free-motion quilting an even better experience and stabilised the quilt well.
Now I use batiste under all of my light patches as you can see in these patches representing snow in my latest quilt. No seam allowances are visible under the white patch and it doesn’t take much time to do.