I think it's worth keeping in mind tweaking different parameters often yields varied levels of improvements. Going from near freezing to hot water yields very different results that you can definitely discern for example. Coarseness of the grind definitely effects results: if you run hot water over raw beans it's not great meanwhile if you could say grind to a point you broke down many molecular bonds in the bean (I'm using the term "grind" loosely here to illustrate a point), you'd lose all the nifty chemicals that you want to taste and so on.

So there's varied ways to adjust each given aspect of preparing coffee (including times of everything, the process itself, the order of the process and so on). And how you tweak each given aspect will have varying degrees of noticeable effect on the taste of the drink (some have almost none). Beans roasted 3 weeks ago probably won't be discernable from beans roasted 4 weeks ago. Beans roasted today might be discernable from those roasted a week ago, though.

Each of these aspects isn't inherently independent of one another either. Coarseness, brew time, and pressure are often very closely linked and adjusting one or the other often requires adjusting the other for desirable results.

Now while some of these sort of tweaks are tiny, combining all sorts of tiny tweaks can result in noticeable larger differences. It might not be obvious what it is because of all of the small component improvements, but the end result is something that, even slightly, is noticeably improved, which is true for about anything.

Ultimately the question is does all this effort combined yield enough improvement that's noticeable. Maybe one small improvement isn't noticeable like adjusting from 92 to 99 degrees. That combined with a series of other tweaks might yield something worth the effort though.

I know when I first started brewing espresso at home I laughed at a lot of advice thinking certain aspects of the brewing process were silly so I'd skip them or just ignore it all together. Things like weighing my beans, tweaking grind size, and so on. My first few weeks of espresso drinks were... pretty disappointing. Why can Starbucks (which in terms of espresso is often lackluster) make better espresso than me at home? As I went down the rabbit hole and adopted more silly strategies, I tasted notable improvements.

It's not just me either, I've had friends try throughout the process and it went from "thanks, that was drinkable" being nice to my not so great coffee to now people saying "wow that's really great, how do you make that, that's the best coffee I've had."

It sounds stupid until you start tweaking all these little parts. I'm not entirely scientific about it, much of it is a hit of an art and inference with science mixed in. I'm at a point now where I think no matter how many slightly improved tweaks I make, I won't be able to tell the difference and it's not worth the time.

From your example, 92 to 99 C might come down to how much energy the water actually has and how precise you can measure it. When you're approaching boiling, some parts of the water probably is boiling and made a phase transition, you're measuring an average of some other part that may not be a good sample of the whole. Those parts that are boiling may result in damaging organics in what you're brewing leading to bitter flavors you don't want, so backing off gives you some margins of error in your measurement. 7 degrees might not make too much difference if it's say 95 and 88 C (a little more time might make up for similar results) but something approaching a critical point like boiling might actually matter.