A lot of what makes some UI great over others is little details in interaction design (subtle animations), color choices, typography, and live content that is very difficult to replicate in wireframes. Users have an emotional response to UI and that's what you want to "measure". Next to impossible to do that with static wireframes. I think all great UI designers should be able to code their designs, gone are the days of separate photoshop/indesign -> code steps, at least until the UI matures.
That said, wireframes are a great tool during product ideation and design. I like paper+pencil as a wire framing tool, and then go straight to working UI.
[1] https://www.amazon.com/Creative-Selection-Inside-Apples-Proc...
I’m also not sure that the inline magnifier is such a good idea, he never gives an example with a fat finger overlaid, I think that would immediately show it’s just not feasible.
I’m also sure that Apple has dozens of user tests with all type of text editing strategies, Ken Kocienda even wrote a book about his process developing text input and auto-correct.
https://www.amazon.com/Creative-Selection-Inside-Apples-Proc...