sevenstrokeroll
I think most people here are talking about a powered approach, but just tighter and steeper than following the PAPI/VASI would allow.
By teaching a VFR student this way, they learn to appreciate the perspective of the approach, and what the aircraft is capable of, and then apply that wherever they go.
By teaching so early on to rely on PAPI/VASI, which will lead you to land deeper, when that same student then goes to a shorter runway with no PAPI/VASI they run off the end, I have seen this happen 6 times now.
3 degree approaches and ILS have their place, but it is certainly not in ab initio training, which is what we're talking about here. By the time anyone gets onto IFR and shiny jets they have plenty of hours under their belt and should be able to tell for themselves the difference.
I think you are fundamentally wrong when you say that every approach should follow VASI/PAPI.