Earlier quoted context omitted.
Directly from the article: "The last remaining draw calls are used to render all of the different UI elements, both the ones that are drawn into the world as well as the more traditional UI elements like the bottom bar and other controls. Quite a lot of draw calls are used for the Gameface-powered UI elements, though ultimately these calls are very fast compared to the rest of the rendering process. " With this minim…
Not sure what kind of projects you've worked on before, but the ones I've been involved in, you wouldn't spend time optimizing something taking Why on earth would they try to optimize how the UI renders when they're having big issues elsewhere?
It's absolutely not the most important, or even in the top 10 most important problems here, but it shows really illustratively how much they care about making a game which performs in an acceptable way. (which is: not that much)
Also, it's not even one or two high-poly models dragging the performance down, what I was aiming at is that the game suffers from death by a thousand cuts - the LoDs are only a part of the issue, almost every part of the game is done in a sub-optimal way. So while the UI is not a significant part of the frame time, if they fix the most glaring performance issues, they will find that there won't be a silver bullet, the game is just a pile of small performance problems all the way down.