Kind of said in the other thread but my position on mods in a short summary is if they're not going to allow them like a few other MMOs do then they should take mods as an active, important, and playful challenge. The players throw down the gauntlet of what the UI should do and the devs, imo, should take that gauntlet as seriously as reasonably possible. For example the addon that basically plays triple triad for you.. maybe not, but there are A LOT of huge QoL, and feature to be honest, mods as well.
If someone at SE isn't actively with responsibility to watch the addons, at least from popular sources (not reasonable to see everything all the time, and maybe a waste of time at that point) then I think that should change. Just.. be careful in case one of the mods is capable of being a security threat. What a terrible story "SE hacked by addon creator" lol. If it needs to be so, just watch youtube videos XD.
IMO to me the shame is whole swathes of people not being able to enjoy it, while the game potentially also being influenced by them (like DBM did to WoW, which FFXIV does have a vaguely similar variant), while also losing a lot of potential QoL and honestly community creativity (although addons also have an annoying side, where they break- anyone in WoW remember an update destroying your addons? lol.......... /tableflip).
The two systems that currently support this have made huge strides over time, and it seems recently, at least one in particular, is getting even more attention. So this issue / concept is only going to become stronger. It honestly took longer than I thought it would (not the devs on these tools, just their existence in the first place- minus the parse specific aspect that's been around AGEs).. but now that it's here it seems to be growing quite quickly.
"How do you know all this!?!?!" Just actually read reddit sometimes... It's posted there semi-frequently, and from there the websites that run it are usually well documented - learning about this is like a lazy 10 second google.
As for safety, none of those tools are safe to say you use within the game or likely here (except reshade like tool), yet FFXIV doesn't want to malware our computers so that's really where the harm is going to come when you're not actively cheating (teleport hax or what have).