It really depends on the mentality of the operator. I have been with those in Oz who think flame-proof suits scare off students and clients and so they insist on wearing their starched polyester shirts. I felt a right prat walking into their midst wearing my full length Nomex complete with ANR helmet.
At a similar operator in a warmer climate (also in Oz), everyone who flies for a living wears Nomex overalls and don helmets without exception.
Comparing the two, who's the greater fool ?