I'd say it depends. I'm a rather happy owner of a Microsoft Surface 4 Pro - and I do see the need for the ability to switch between modes (and I can't say MS has exactly succeeded here, but also not entirely failed). Granted, I don't really see why I'd want UI/UX adapted to a screen 1/8th the size - but to a certain extent "tablet mode" and "tiny tablet mode" are probably more similar than "tablet mode" and "laptop/desktop" mode.

I'd have to test it of course. One thing that MS has not managed is make a UI that works well for high resolution screens (for legacy applications, that is). But I guess one of the reasons I'm positive to the use of "convergence" buzz word, is that it could mean that all GUI-frameworks are expected to scale in a sane manner. I absolutely understand the skepticism that it will end up being "a worst of all worlds" UI.