Aye, the Vulcan had PTFE in conjunction with a buffer washer. I had one. Seemed to work well enough.
If your PTFE'd Diana's have been working well for you since 1986 and the seals have not been hammered out of shape and worrying the cylinders then I can respect your point of view on the subject. It's not as if your trying to convert the masses.
I will stick with original (pardon the pun again) leather, myself. Works very well for me.