Hey tom,
So "the grey zone" can be defined in different ways. There is also a black and white zone for me. Your elephant if in the white zone, has that helmut in the black zone. There is nothing about that helmut (or a car) that cant be done with NURBS... Although for patch modeling a car, you need a robust toolset. The helmut? Not so much. Also, your level of proficiency comes into play with the grey zone. Alot of NURBS guy may whip that helmut off pretty quick. Alot may struggle with parts. Etc.

A human face? Poly's for sure.