The "I prefer to be native" mind is clearly gamers that went thru the switch to LCD. at the time, getting good 1080p performance was hard but not running the panel native resolution was a huge problem.
I still think people having 1080p should try to run native as much as possible. But at 4K, the amount of pixel, the surface area that someone can see normally and normal viewing distance and stuff, make these technique very useful. I wouldn't mind turning it on at 4K but that would bother me at 1080p. Unless indeed, i am running a very low end GPU.
That give us way more option for getting maximum performance while keeping good image quality. It would still be a good idea indeed to turn down many of the placebo Ultra settings that have great performance hit but i think that i would prefer to run some game at 4K FSR quality High or ultra than 4K native medium. But so many testing to be done.
A point worth nothing is there are many settings available to the devs like how many sharpening to apply in FSR. I suspect that over time, people will get used with the technique and extract better image quality from it by fine tuning the settings.