The primary function of the Windows key has been to open the Start menu since the day it was introduced. The modifier key aspect of it was always secondary.
On my keyboard, it's not even physically labeled as the "windows" key anway, it says "option" (or, if I didn't have things re-mapped, "command").
(I apologize for the historical artifact of a webpage linked below)
[1]http://members.fortunecity.com/buchta/PCTourCD/files/win/Ove...
My memory of Windows was that the Win key worked as global system modifier key. But it's been a while now...