Strange but true: Z-coordinate not zero in paperspace, when e-snapping from model space

Entities created in paperspace , using e-snaps from the model in a viewport inherit Z-coordinate.

This seems strange since paperspace would be expected to be just that: flat as a paper with Z=0 (it is like that in AutoCAD, or was up to 2000 that I am familiar with)

What is the meaning of Z in a space intended for annotation and sheet styling?  It creates more problems, in my case, than the added information offers as a possible advantage.

The DS flatten command MAKEFLATSNAPSHOT is too complicated and of limited scope