I don't understand the mentality of people who disparage the folks who like to use a centering tool like the giffin grip. I understand there is a line somewhere that once crossed, puts into question the notion of "handmade", but the GG and tools like it are nowhere near that line. Why not say we shouldn't use electric wheels? It's not that different a notion.
I hope there are no teachers out there that start their students on GG's. I don't even bring one into class, but then I teach only beginners. For more advanced students who have learned the basic centering techniques, I don't see a problem.