This knot can be useful if you need to tie a toe hold in the middle of a rope. This knot is very useful when a loop is required but neither end of the line is available. It can also be used as a seat while being hoisted as there are two secure loops as opposed to the traditional one loop bowline which makes a great much much safer seat.
Just like the bowline knot this knot has the rare ability to be easily untied after a heavy load or shock is applied to the knot.