As long as it pretends that it has multiple pages, I don’t see the harm. Not re-fetching and re-rendering navigation elements is a good thing, and you don’t have to break the back button, address bar, and so on to do it.
Honestly, there should probably be a standard HTML attribute that tells the browser that internal links will always send this element in the same way and it should not be re-rendered.
As long as it pretends that it has multiple pages, I don’t see the harm. Not re-fetching and re-rendering navigation elements is a good thing, and you don’t have to break the back button, address bar, and so on to do it.
Honestly, there should probably be a standard HTML attribute that tells the browser that internal links will always send this element in the same way and it should not be re-rendered.
It’s called “frames” and we’ve had them for years. I feel like there’s a meme template that would fit this…
Frames absolutely obliterate the back button and address bar, though.