> I used to bevery enthusiastic about continuum in Windows. But now, I've come to realize that the interface better be separate for different usecases - plus, no one want to plugin their phone and use it for work.

You seem to have a misunderstanding of how continuum works in Windows. The interface is separate when you hook up a phone into a dock (it's a desktop interface) and the newer devices can also do it wirelessly.

Windows went with a "similar UI language" for all platforms but still maintained huge differences between each platform because that made sense. It was never the same UI.