It seems to me that what is being asked here, is not if it would work to do embroidery (such as flowers or animals) in place of quilting, but to use the machine embroidery stitches as opposed to straight line stitching. Most machines these days will do some fancy stitches, and these would give it an appearance similar to the "crazy quilts" made in earlier days.
I think this would give the quilt a very unique appearance.
Perhaps try it on something else as an experiment before you do the whole quilt. Sounds like a good idea. Let us know how it turns out.
June