I use brightwell coralamino. Not for growth or coloration but I find it helps LPS corals grow flesh. Specifically damaged or recently fragged ones. Only “evidence” I have is that I used to have a 2g pico. No filtration or dosing, just an airpump. I had a hammer coral that was almost killed due to fragging. Like 1-2 weeks after starting dosing aminos, the hammer was starting to grow new tentacles where it had otherwise just been stable. All else aside, it was the only thing I changed during that time period and I did see a noticeable difference. With no filtration, dosing, and a consistent routine up to that point I definitely did see a difference that I correlate to the aminos. Agreed that excess aminos will cause cyano but only at a certain dose and its pretty easy to just dial it back to avoid that. I used to dose right up to the point of cyano, using cyano as an indicator that I had too much.
1/3 head of a cracked hammer coral:
Hammer after a few months: