For instance let's say the company is in Berlin, having an office there means employee will need to be at a commuting distance from Berlin wether they actually commute or choose not to. Recruiting someone in Amsterdam becomes a difficult decision, and employees in full-remote still have to pay Berlin area living costs just for the potential commute they could have to do.
And that's assuming online discipline is exemplary and you don't have a "left out" effect between those on premise and the others online.
Basically the choice would be between solving the privacy issues you raise, or solving the logistics/disparity issues raised by other solutions. I kinda feel like the privacy issues could be easier to solve than the others.
Given that today most offices seem to have an open plan, your two sentences seem contradictory.