PTFE tape is not for compression joints. Use Boss White.

Wrong. Been using PTFE tape on Compression Joints (where needed) for 30
years. Boss White is not suitable for potable water. Must conform to BS
6920, it doesnt. see www.tool-up.co.uk/shop/diy/MISBW.html

Somewhat unnecessarily, though!

You're right about Boss White, though. Should only be used on heating
primary circuits, really.

Christian.