You aren’t wrong, but I still see two distinct benefits assuming there is an IR reflective or absorbent coating that can interfere with facial recognition.

• For non government entities it makes direct tracking of individuals much harder (i.e. if you decide not to carry your phone or smart device any one company probably doesn’t know who you are).
• For government entities it’s about making their job harder and increasing the error rate. You are right that they can still track someone via those means, but any time they have to correlate data or use multiple sources it does become more resource intensive in some way.

Realistically will either of the above matter? Probably not. For it to be effective a large portion of the population would need to care about their privacy, or even their principles above convenience, which they usually don’t. However, I can’t control what other people do, only what I do. So in this kind of situation I do my best to be a good example of the behavior I would like to see from others and do my best to not contribute to the Prisoner’s Dilemma or Tragedy of the Commons.

It’s not much, arguably it’s basically nothing, but it’s what I have.