I personally don't differentiate between week-days and weekends. I often work on weekends (and probably just as often take weekdays completely off).

But generally, when I speak about vacation time in the context above, I mean it as in large continuous chunks of time during which you only unwind and regenerate (and ideally travel to some interesting place off the beaten track).

That does make sense, but I suspect most people do differentiate between weekends and vacation/holidays which explains why some comments are reacting to your suggestion when it's actually quite sensible.