Comes down to the model of trust as much as any threat model. I don't need to perceive or even conceive of a specific threat to want to safeguard my privacy, even aggressively if I so desire.

If the threat model includes surveillance capitalism, then the faraday cage is actually a pretty reasonable counter measure.

It blocks nfc, bluetooth and wifi. The last time I checked, airplane mode left those on, and so did the toplevel “turn this radio off” buttons in iOS.