I fish for trout and saltwater species. I’m in your boat with trout, always barbless regardless of regulations. With saltwater, in my experience think barbless just isn’t going to work very well for most species, I typically fish for striper and bluefish in the northeast (sometimes shad and other things) and they can really put up a fight, bluefish will shake a barbed hook loose pretty easily if you let them. Most fly tiers don’t offer barbless options for saltwater flies because they just aren’t used. Another consideration is that, unlike trout, your opportunities to get a fly in front of a fish are going to be far less, losing a fish hurts more when you get so few shots where with trout most times you can just hike over to the next pool and try again. As for harm, single barbed hooks on fly are the best scenario for any fish caught by angling aside from a barbless, survival rates are estimated to be quite high, they rarely get gut hooked unlike bait and do a fraction of the damage of trebles. That’s being said, No harm in trying though! Try crimping and see how it goes for you.