make sure that the spaces between the quilting aren't too far apart or the batting will shift. often that's why they say not to wash it. if the areas between stitching are large, add stitching for stabilizing. when you wash it, make sure you dry it very well. it always seems dry when you feel it, but on the inside it's often still damp and can mildew. better overdry than damp inside. don't even ask. btw, that looks like a comforter that was made to be used inside a duvet cover, and you might consider using it that way so that it needs to be washed less often.
edit - i just looked again and it looks like the kind that isn't stitched in boxes at all. it's stitched in the pattern that allows the filling to move around inside, allowing you to shake it around so you can shift it to where you most need the warmth.
for example, if you have cold feet, you can shake more filling to the bottom. we had one and that's what it looks like to me. (do yourself a favor and even out the stuffing and stitch it in place). it was meant to be covered. btw, when it got washed it weighed at least, .....oh, ...... 4,000 pounds. so don't think you can line dry it :lol: :lol: . count on drying for at least 4 hours if not more. it's worth it for the warmth and light weight.