Tank main here, not using parsers or any other addons and completed E4S. My guild is not willing to go for Alex Ultimate, so I have no idea how we would fare. I dont need any addon while actively playing, but I think some of the information to figure out openers, rotations and priorities is only really possible to figure out with a parser.
As such I wont claim I dont benefit from third party addons.

I personally dislike and disapprove of addons that run during a fight in order to manage/alleviate the difficulty in any way. If damage meters would only spit out an end number after combat is over, that would be fine with me too. I find it hilariously out of date for FFXIV to stick to the ancient MMO design idiocy of building complex systems, and then trying to hide as much as possible information from the playerbase.
But anything that makes this overly easy game even easier should be banned.