All this is fine for academic discussion, but the reality is that many, if not most, helicopter operations are simply not feasible using Cat A criteria. Many helipads simply don't permit Cat A operations. When making an approach or takeoff, I try to set my priorities on what the most likely cause of bent metal will be, and the most likely cause is seldom engine failure, especially on approach. Having an aircraft with unlimited power and unlimited range would be nice, but it's an illusion. The bigger and more powerful the engines, the shorter the range and the more expensive (and thus unlikely to be purchased) the purchase price and maintenance costs. Cat A is nice in theory, but impractical for use in the real world of helicopter operations, where max possible payload and range are the real drivers. Given the statistical likelihood of engine failure in large modern turbine helicopters, that isn't unrealistic or even unsafe, unless taken to extremes. I use whatever approach technique I consider the safest under the conditions encountered, and that technique often places the possibility of engine failure down on the list.