How do you define (meaningful) choice?

[Renathras]

As you've phrased it, the correct answer isn't a set thing only because you've neither precisely formulated the question to be answered nor precisely formulated the criteria by which potential answers are to be evaluated:

• If the question is, "which action maximizes DPS for this GCD, everything else be damned" and it's theoretically possible to cast Broil IV safely, then the correct answer is Broil IV.
• If the question is, "which action is expected to maximize my personal DPS for this GCD" and there is a 220 / 295 ~= 75% chance or better of casting Broil IV safely (where "not safely" means, say, tanking the floor), then the correct answer is Broil IV. Otherwise, the correct answer is Ruin II.
• If the question is, "which action maximizes the party's DPS for this fight" and there's a non-zero chance you might wipe the party if you cast Broil IV, then the correct answer is Ruin II.
• Etc. Etc.

The choice between Broil IV and Ruin II here isn't meaningful because you're trying to choose between the actions themselves. It's meaningful because you're trying to decide which question you actually care about, and then trying to answer it with imperfect knowledge (do you really know what your chances are of pulling off a Broil IV are?).

Yeah, but the point is, those are actually interesting questions and thus allow for choice, especially when the answer ISN'T automatically clear.

Contrast Medica 1 vs Afflatus Rapture or even Medica 2. In which case is Medica 1 ever the correct choice? Or Cure 1?

I'm sure if you work hard enough, you MIGHT come up with something for Cure 1 (if the person will die if they don't get SOME healing within 1.5 sec, and where Cure 1 would satisfy that, and where all your instant cast and oGCD heals are on CD), but it's a pretty wild case that is exceptionally rare. On the other hand, there is no case for Medica 1 unless you have EXACTLY 900-999 MP (but not 1000 where you could cast Medica 2) AND where you only have one Lily AND can't spend it due to either overcapping or anticipating a future movement you need it AND you can't cast Swiftcast.

...which isn't just rare, it's effectively impossible to ever happen since MP ticks will almost always take you above 1000 if you aren't to 900 yet, and you're almost always going to be well above this, and even if you aren't, you likely have oGCDs or other tools available to use.

That means Medica 1 is basically NEVER a choice from level 50 onward, and Cure 1 is only rarely a choice before about 52, and never after that.

Broil IV and Ruin II actually offer something, Cure 1 and Medica 1 do not.