I thought this Standard Property "Public Date/Time" should do it.
What's the use then? Do I have to check myself for this date before allowing the user to view the page or what?

that date is just for the page creation.

turn on advanced permissions.
goto the page permissions
mess with the drop down that controls what permission set you're looking at..

this lets you control timed releases across groups & users..
-frz

The advanced permissions / times allows me to set access times for a page. But essentially what I want is this scenario:
Content editor makes changes to page. Previews. Content admin likes the change, but wants to release that version to the public at midnight.

Through those controls I can turn off a page & turn on a page, but it seems the permissions/times are page based, not version based.

you're correct. not sure what to do about that one.