I actually have some sympathy for your position that Prisoner's Dilemma is useful to study, but Newcomb's Paradox isn't. The way I would put it is, as the problems we study increase in abstraction from real world problems, there's the benefit of isolating particular difficulties and insights, and making it easier to make theoretical progress, but also the danger that the problems we pay attention to are no longer relevant to the actual problems we face. (See another recent comment of mine making a similar point.)

Given that we have little more than intuition to guide on us on "how much abstraction is too much?", it doesn't seems unreasonable for people to disagree on this topic and and pursue different approaches, as long as the the possibility of real-world irrelevance isn't completely overlooked.