I use a rolling hitch when I'm putting away my Tanzer. I use it to pull the lines tight so that they don't chafe when I'm gone. It stays tight as long as you pull it along the rope or whatever you have it tied on, If you go at a right angle its not so dependable. Wikipedia suggests that it would be useful to help pull a rope to create slack in case a sheet jammed a winch or a block. I guess it would work.
Tying a Rolling Hitch
The Rolling hitch is strong as long as the pull is in the direction of the object it is tied to, not at right angle. If you look at the last photo, the line going downward will be pulling towards the left. In that way it will be stronger. It is not very strong on small rope but holds better on larger lines.