poor performance is not a pre-requisite of bad experience. in reality it's a combination of UI & UX that contributes the most to bad experiences. not poor performance.
so don't focus on poor performance when there is no effect. and even when there is a marginal effect, UI & UX matter a lot more and could even negate the poor performance aspect.
so my point: UI&UX > performance. almost every single time.
all of this is based on various analysis i have done for a whole slew of clients dating back to 10 years ago.
I'm not sure what point you're trying to make outside of pedantics.