The game does a very poor job when it comes to explaining how jobs play to the players, there are also nuances that are not logical.

I have met a Black mage player in a Nier raid who was constantly casting the wrong spells, i managed to get into a talk to him and he didn't even know how to get 3 Astral Fire stacks without casting Fire 1, i managed to explain the basics to him after the raid, a rare occurrence that someone actually wanted to listen and learn.

I think most jobs suffer from skillbloat and if you aren't already versed in game mechanics it is difficult to understand what the tooltips even mean.