Ahhh....land v. sea?
Perhaps the difference rests within the element of this technique that you are NOT seeking a flyaway speed with the CatA backup departure.
Once you've cleared the initial obstacles which may impede the capacity to alter the nose of the craft, you gain the ability to alter the direction of the nose of your craft in order to better utilize the relative wind speed available that day.
The wind speed, the more the merrier, actually allows you to better manage your power buffer and back away bit by bit. It is by NO means a rapid response technique.
Should the worst happen, mechanical or met, you have the capacity below 150'(approx.) to execute a single engine approach right back down onto the helideck or LZ dependent upon relative surfaces.
Sorry, not meant to be confrontational, just conversational....
hope this is a better job of restating the concept?
Kevin