Saying "another job has higher aDPS means it will burst higher!" is a total fallacy that fails to account way too many variables when it comes to burst, one of the bigger ones being that a higher aDPS job tends not to provide any raid buff in counterpart, and is generally tuned on its raw base damage potency higher than the others (namely SAM, BLM to name the obvious suspects). It is true that one has higher aDPS than the other since it has higher burst potential, but saying that it does bigger burst because it has higher aDPS is a total non sequitur. Only one implies the other, else you'd get DRK having higher aDPS than anybody and yet, that's not true, but it's still the biggest burst job in the game with NIN. They do not, however, have higher aDPS for the simple reason that their base potential power is lower than SAM for instance, because they do provide raid buffs (and DRK is a tank anyway).
aDPS is a metric that only accounts for how well a team plays into their own raid buffs, and is also unique to a single team composition (a different composition will play with different raid buffs, and the metric will change a little at equal performance level). On a minor note there, rDPS also has a flaw, which is that it also tends to skew in favor of raid buffers (like DNC) that are playing in selfish heavy compositions, which naturally inflates their rDPS charts. This is due to the fact that both metrics are a complement to each other in that they try to funnel a rating on an individual when in reality the performance is at a team level. To make it simple, if you account for aDPS, you do not account for how well your team mates played into your buffs. If you account for rDPS, you do not account for how well you play under your team buffs (because that value is redistributed to them).
In short, even though as I said above you can definitely find small flaws:
- rDPS is great to compare what each job provide to a team on a GENERIC fashion.
- aDPS (the successor to raw personal dps, aka the same with the solo buffs like cards removed to prevent padding) is an old and flawed metric that has way too many variables not accounted for. It CANNOT be used to compare burst potentials, even though it is definitely affected by them. It's just good to know how you played into your team raid buffs for a specific run only.
- nDPS is the metric you're looking for if you want to know the base raw, unmodified, unbuffed power a job has on its own. It is the best tool at your disposal if you want to know how well you're faring compared to other people playing the SAME job on a rotational basis only (still affected by the native rng nature of each hit but that's another story).
If you want to account for a job pure burst potential, you'd need to take a nDPS chart and extract the 20ish seconds that cover each burst every 2 minutes.
Burst is important enough to take into account because it is often reflected in charts and if you check them on a regular basis (every couple of weeks) you'll see some jobs moving up or down slightly on rDPS for example, because people are adjusting to the fights themselves, and the way jobs can play around downtime or especially kill times (that will allow or not another burst before the kill) means that nothing is completely fixed into stone. As people gear up and progress, some jobs suddenly crop up a little because they fare better with certain kill times, a little more than others.
Edit: I do believe fflogs is focused on the wrong part of the play, which is personal performance, which also comes from wowlogs I believe (?), and more generally how as a society we value things. Or maybe that's because fflogs favors this that everybody follows, hard to say what came before between the egg and the chicken. Either way, both feed into each other and we end up with a maximized individuality, with individually focused metrics instead of having a bigger focus on party total dps and kill times, which always seemed the more natural way to go about things, to me at least. Don't get me wrong, there is still value in individual metrics, but it's pretty telling that percentiles on individual pages are centered exclusively on individual metrics rather than party wide.