The message ews.net
from "Doctor Drivel" contains these words:

"Wherever possible, use a layer of PTFE tape around the thread of the
compression fitting. This tape will be pushed into the thread by the
tightening of the nut and seal any overlarge gaps within the union of the
threads. "

Can't see why it matters whether the threads are sealed or not. They're
nothing to do with the hermeticity of the union.

--
Skipweasel
Pay no attention to that man behind the curtain.