Sustained turn rates are pure academic exercise that bears almost no relevance to actual dogfighting. Instantaneous turn performance and turn radii will almost always be the deciding factors when the pilots are allowed to do what it takes to win instead of following a rigid theoretical flight pattern. Yet people are obsessed with sustained turns for some reason - maybe it is the unrealistic and simple geometry of sustained turns that allows them to draw simple circle pictures, while maneuvers with varying turn radii, speed and a 3rd dimension are more difficult to imagine.
Nonsense. I agree that sustained turn rates numbers are academic in nature in that they are snapshots under specific conditions but that's true of most of the aspects of fighter performance comparison including corner, NRG addition rates, and turn rates and radius but they are hardly the "pure academic exercise" you think they are. Before flight they serve to give you an understanding of the relative merits and weaknesses between two aircraft. In flight, they are actually more "rule of thumb" than precise answers because of the dynamic nature of ACM; however, they still serve to influence your strategy and decisions in a fight. It's a poor fighter pilot who doesn't understand how to max perform his airplane in all parts of the flight envelope (what it's really capable of) and how it stacks up against an adversary. It's also a complement when a pilot is said to "fly by the numbers" in that he knows precisely how to get the maximum performance out of his plane.
You do use these numbers and concepts during a fight even if you personally don't realize you're doing it. That's how you recognize certain scenarios or conditions and say "hey, I know I can out rate the guy here," or "here's where I can gain separation because of my acceleration rate is better than his at this altitude," or "now's the time to go vertical because I know he's burned lots of E to get the angles he has". The OP's original question was really about knowing the consequences of his actions on his own aircraft, i.e., how much is a max instantaneous turn right now going to affect my NRG budget? Can I afford to trade-off altitude for a max performance turn or should I extend for separation and rebuild E? Do I have enough flight path separation to lead-turn or should I extend vertically for vertical separation? It also sounds to me like his biggest problem is he's doing precisely what you advocate, i.e., focusing on instantaneous turns and radius vice managing his E.
Nobody teaches that you "do this, this and then that and you win," not if he's a legitimate instructor. Some people do mistake discussions of things such as one and two-circle fights as a cookbook; "First add two parts G and one part speed and let simmer at full afterburner for two turns," but it's not a cookbook and it's not a "rigid theoretical flight pattern," it's a method. ACM is a dynamic and fluid environment and there is no number or method that is always right but that doesn't mean that fundamental principals don't apply. If you've ever diagrammed and analysed a fight in a debrief you'd see all sorts of instances where these allegedly "rigid theoretical flight patterns" are used. They're not all text book pretty but they're there. You'd also see most fights exhibit the use of both max sustained and instantaneous turns and you'd see where the rest of fighter performance comparison criteria such as radius and acceleration come into play.