Dear dnes: Your gif looks like a special case of a winch.
My impression of it is, though, that it would have a rather small mechanical advantage. And the pull on the rope would not be kept centered, so that the barrel would tip sidewise and could not be controlled.
If I remember after more than sixty years since I had a first year physics course, mechanical advantage is ratio of force time distance traveled operator's hand, divided by force (weight) times distance traveled by object. In the case of the barrel, the ratio is one. The barrel will move up the slope pi times D, when rope is moved pi times D, so there is no mechanical advantage. The slope is one of the basic machines, so force require to move barrel up the slope is less than force required to lift barrel vertically.
But in practice, it could not be assumed that the barrel would not simply slip and rotate in place.Just a dolley would be better than just the rope.
