the why not is....
as it breaks down it will become wet-globs- which will then cause globby lumps in the quilt- and sure 100 washes down the road it may all be gone---but in the mean-time--
better to tear off the majority of the paper- you don't have to worry about the little bits that stick in the seams- those will disappear fairly soon & completely- but larger pieces will glob up-then take longer to break down.