I don’t get your point. Yes, there’s a lot of eavesdropping techniques available to actors with nation state capabilities (or with a lot of time, money, and expertise). This is another one of them. It’s good to be aware of things like this because it helps you better understand threat modeling for applications that require serious hardening.

There may also be unusual applications of this, like the traffic counting mentioned by another commenter.

(For anyone who needs hardening against things like this, you need a SCIF.)