I have! And I can tell you, they don't work as well as you think they do!
They only lower/increase the saturation for some colours, and you can change the amount. This is fine for some instances, I won't lie. But when the instance is all the same colour, such as E9S or P3S, you're not going to get much mileage out of it. Kampeos Harma was literally pants for me because it didn't matter if I had the in-game filters on. Deuteranopia didn't make a marked change for me to understand which was which, and Protanopia barely made a noticeable difference. It was both horrifying for me and hilarious for my friends to just see me staring at the computer monitor gawping because I was like "I... I can't tell the colour, what the hell!". It was an absolute GODSENT that they actually put squares and triangles, because I'd be so screwed.
Or take my early forays into Bozja. I did realize that the AoEs on the Mandragora FATE had a pattern, but I kept dying until I learned what the patterns were. Because turns out, I kinda can't go in with colours, and changing saturations doesn't exactly help. Since, you know, the darker you make a blue, the closer to purple it looks.
Or, you know, my absolute favourite... Having the C and D markers look identical, just with a different brightness level (C is brighter than D), and then I turn on shaders and SOMEHOW D IS NOW THE SAME AS A INSTEAD.
:facepalm:
:internal screaming:
Turns out C is blue, D is purple and A is magenta. Literally the colours I struggle with. Now, you might think "well, you can just read what's on there". And yeah, it's stupid that I don't. But I immediately go for the bright flashy thing rather than reading it xD this one's on me, but it does trip me up to go for the one I think is right, only to then be like "ABORT, IT'S THE WRONG LETTER".
...So yeah. The in-game shaders really do only take you so far, and it's the presence of patterns and other visual cues that tips me off. Another example is Mt Gulg, where before they added the glowy border to the AoEs in there, I had to really squint to figure out the differences between "glaring white" and "pale yellow". And no amount of in-game shaders are gonna help with that!
Like, I won't say they're absolutely useless. But they're not as robust as you'd require for a game this heavy on telegraphs and identifying animations. Because on other games, either stuff is quite stationary or I can just see the boss's animations just fine to react to them. FF14 is a choreographed game with telegraphs.
And like I said over yonder... I have it MILD. I can't even imagine how worse it is for people with full-on colourblindness. Because my main concern is that I can't go overboard with the shaders because a) I don't need to, and b) it makes the game look darker, which doesn't help in distinguishing darker/lighter hues. And hell... I don't even know if the setting I'm on is appropriate for me. Because I supposedly have Deuteranomaly? But the Protanopia settings help sometimes far better than the Deuteranopia one does...