On my Mac I almost laugh at how massive the borders are to accommodate the freakishly large corner radius. The next version might have round windows at this pace.
I found that there's one upside to it: the empty space "outside" the corner still counts as part of the window, but it also works as a hot corner for drag and drop window resizing purposes.
That said, it's still comically large, and actually intrudes onto app UI in some cases, especially with scrollbars.