What Is The Point Of Leveling Trusts?

[AngelCheese77]

I like the Trust system, both in FFXI where it started and now in FFXIV, and I think I know WHAT leveling Trusts achieves but I fail to understand WHY one would do it.

It seems to be, so far at least, every dungeon on the MSQ will have Trusts at the correct level and assuming this is SE's intent going forward then what is the point of re-running the previous dungeons umpteen times simply to get the 'old' trusts up to whatever is the current level?

What am I missing here, as from what I know at the moment you end up with nothing you don't have without doing so.

This of Trusts like Squadrons from your GC at higher level dungeons. They brought them in for mainly DPS bad queues in ShB dungeons (only dungeons Trusts can be used in rn).