I believe what the OP is asking about I’ve heard of as plumber’s tape, what you’re talking about I’ve never heard called anything but teflon tape.
If you google-image search “plumber’s tape”, the results are about 50/50 pictures of teflon tape and hanger straps.
To be pedantic (and legally correct), there’s no such thing as Teflon tape. Teflon is a trademark of Chemours (formerly DuPont), and there is no TPFE tape authorized to be sold under the Teflon name. Chemours frowns on the use of the name Teflon tape.
Don’t plumbers install air dams anymore to prevent water hammers?
That’s copper plated steel, not copper.
It’s not the sprocket edge from a super-heavy duty continuous feed dot matrix printer that uses metal paper?
Bow down before Okidata Supreme!
Yes. But hammering can be unpredictable, especially over the years as the plumbing system is altered, repaired, pressure changes, etc. They have to be installed in the right place or they don’t do any good. Not that it matters for strap hangers, pipes still need to float, they should not be rigidly attached to the structure.