Slosail,
Your points are valid. If someone is building from a stock design where they provide full scale section templates, all this lofting work has been done ahead of time and these approacxhes are not needed. Also, if a tortured ply design fits your needs, then as a home builder, that is easier to build.
So what is the method good for? If you want to design your own hull shapes and if you want build of higher performance materials that require either male of female tooling (and you don't have a shopbot!).
I think a hot wire rig is an interesting idea. Might be another way to do the same thing.
I apologize for having so many troubles posting pictures. This kind of thing is very hard to explain without them. But, I think I have a few posted now and I will add some shots of the finished mold and the "shaping tool"