Measurements for DPS contributions (Please SE...)

[Atomnium]

Right, but a tool that says you have XXX dps does not tell you what to do in the scenario you described. You learn what is the best choice through understanding your abilities & the fight through experience.

And this is exactly why a parser should be a mandatory starting point (and later a well needed friendly tool), it will show your weakness and force yourself on self-improvement against a static and harmless enemy.
The way you will dodge in X fight or learn to coordinate your movements will then be based on the training you dedicated to your DPS.

A parser will not do the work for you, it doesn't think, it will not teach you how to dodge, it will not tell you when using a specific CD at a precise moment, it doesn't forgive . It will just show you a possible weak spot within your gameplay in order to solve it by your own.

If there was no DPS check fights in FFXIV, I would say... As long that your rotation is correct and you do fine with dodging / movements, we could be like "eh, who care, let's keep it this way"
But that's not the case, FCOB proved once again that tight DPS check fights are a strong and important point when the DEVs are actually designing such contents. A parser is a necessity in your learning progression for them.