Does the ffxiv tutorial ever tell you how to use the target circle?

[Settiesama]

Even without needing to know which way a target is facing, I’d never turn the target ring off - it’s valuable in crowded melee situations to keep track of where your target is - if they move around, or there’s more than one of that monster, or you changed targets using the enmity list and need to see where your target physically is.

There is a large marker above the current target that tells you where it is. You don't need the ring for that.