Hehe....there's a "smiley" that doesn't get used very often.
I was pretty much thinking the same thing. Not that the fur gets digested...but that, as you say, helps to bind the waste together. Consistent, properly formed stools are an important part of any digestive system. (I can't believe I'm typing this while trying to eat lunch! LOL)
I may be erroneously applying what I know about mammals to snakes...but from what I understand...a long period of time having loose, runny stools (when an animal was designed to have solid "logs") can weaken the intestinal muscles and eventually make it very difficult to pass "normal" stools.