Thanks, very clear and comprehensive answer.
I always miss something really obvious… An RF-sponge as an AC cord, what a great idea, hah.
But are there any applications where foil (in a spiral pattern maybe? Some geometry to avoid the mentioned issues…) would work as a maximal area signal conductor (not shield) and not be superfluous? I guess not in unbalanced interconnect cables unless they have good additional RF protection, like AudioQuest does with their fairly thick copper outer shields?
Digital…?
Even if foil’s only proper place as of now is in shielding, I’m still interested in how skin effect exactly behaves in minimal thickness conductors.