Using it the right way around with 10' missing made it into a nice polyleader line. It works fine this way, however, like WCs everywhere, it needs the head out of the guides to really work. That creates a big D-loop, big distance, and not much accuracy. At the end of such a cast, if you're flogging shot and an indy, then you might not get much turnover, especially into a headwind. The reversed WC needs only about 20' or so of line out to work on the spey and even less overhead.
The reversed line was intended for turning over lots of "stuff", (big) pocket water speying, short line casting when working tight, heavy wind days, little D-loops when next to the bank or overhanging trees, a short casting stroke when room is limited, or where accuracy is important (an unanticipated benefit). The thick belly also doesn't get dragged under as much as a thin tip. The beauty is -- you can use it the right way around or flip it to suit the situation as you work your way down the river.
I find that some of our GL rivers (the Catt in NY, the Credit in ON) have pocket water stretches and big flats. A standard WC sucks in the pocket water situation but it's nice on the flats. This rig handles both.