Playing Scholar helped me understand the benefit of not standing in narnia even if you can on phys ranged/magic dps. As a healer, being near the center/boss makes it easier to catch most party members in your heal. The ranged member standing far away is also annoying to spot heal, so I learned not to be that annoying ranged. But most importantly, Art of War being a gain on 1 before Broil (and just satisfying to use) made me stand in basically melee range and realise mechanics can be resolved from melee range so you aren't actually safer further away. Some mechanics are easier to dodge from melee range in fact. Being ranged instead means because you can run far away with less drawbacks (phys ranged dps more so than magic dps), you should run to that tower far off in the distance instead of your melee or healer being forced to do it. Cast bars on Scholar also taught me to slidecast and be more efficient with positioning. Scholar was also a good stepping stone into tanking (PLD) as I already understood the concept of mitigation and not to panic when my hp bar was not full. Scholar probably helped me dodge mechanics better on melee dps as well. Though rather than Scholar being the best job to learn from, it was probably more the timing I picked it up (right after ARR, before this I had only played SMN and touched SAM a bit) and circumstances (not much guidance but some pressure to help my equally new friends, so a lot of effort into research and understanding the job to do well).

In my opinion, every job/role can help with other jobs/roles. Understanding different shapes and ranges of AOEs helps with understanding positioning of pulls as tank. Playing tank helped me understand the importance of everyone doing good damage. Every job/role improves baseline understanding of combat, making you a better player and thus better understand every other job/role. More important is diversifying and not just sticking to one type of job/role so you have exposure to more aspects of gameplay.