I like the trusts, even if I only use them myself for one reason: they make me care more about the Scions.

Up to ShB, it felt like here's this group who are supposed to be "at my side", and yet every time I have to deal with something they suddenly are indisposed. Oh, they need to go do a thing over there at the same time, sorry... just find some random other adventurers to accompany you!

I went through ShB doing each first run of a dungeon with the trust (that one time you don't have to level them to do it), just to see their various reactions and interactions. And by the end of ShB, it felt more like they really, genuinely were at my side through the adventure in a way that it had not in previous expansions. And things like Alisaie's reaction to the second boss of Holminster Switch (and Alphinaud's reaction to Alisaie)... they were little touches, but they added to the story and to my view of the characters, fleshing them out.

And then I just go back to doing DF runs, because I have come to enjoy the social aspects of the game. (And also leveling the trust so that I could run the dungeon with them again is kind of painfully slow for the minimal payoff.)

But I also remember a much-lower-level me who was nervous as heck about running dungeons for the first time, and let it stall her out on advancing the questlines. (And then I leveled up and got over it somewhere in late Heavensward content.) And I think trusts could also be a benefit there, because—story elements and interactions aside—they will let someone who is nervous about doing their very first run with other people feel out the dungeon in a 'safe' manner, where they don't have to worry about other players being impatient with them or whatnot.

And honestly, given how often people argue about playstyle on this forum—pull big, pull small, should folks fetch extra mobs if the tank is slow, or let the tank determine the pace regardless, etc.—I'm a little surprised more people aren't in favor of an option that lets dungeon runs go more smoothly by letting someone who wants to be really cautious on their first run have the option to do so outside of Duty Finder.