Nice dodge. Whatever, I'll let it slide...
I would expect a more informed opinion from a moderator...The Isometric Perspective is a close cousin to true 3D, but it isn't really 3D. It's as you said: With every graphic being a sprite, if you were to somehow turn the entire gameworld sideways, everything would be paper thin (ala Paper Mario). This perspective is a nice trick to look and play 3D, but it isn't true.
Not to mention how horrible the IsoPer is for platformers. Don't even think of trying to make a pixel-perfect jump. This is one reason why Super Mario RPG frustrates the crap outta me! I hate the IsoPer, period!