The entire premise of this article is wrong and derived from a misquote. Kristian Høgsberg, in Wayland stated his goal was a system in which "every frame is perfect, by which I mean that applications will be able to control the rendering enough that we'll never see tearing, lag, redrawing or flicker."
It had nothing to do with "if I take a screenshot of your app at any moment, it must make sense." As others here have pointed out - this entire article is very poorly conceived.
The entire premise of your comment is wrong and derived from not understanding this quote of the author:
> Wayland is talking about the technical side of things (modern GPU stacks are very complex and Wayland is trying to take control back) but it could be applied to UI too.
Misquote or not, the article is bang on and I think a better interpretation of that sequence of words anyway.