Yeah, it's a bit of a push versus pull distinction: Fancy Zones sets up "zones" on the monitor that you can push applications into. A tiling window manager pulls new windows as they appear into non-overlapping "tiles". With Fancy Zones a window typically overlaps by default (just as the Windows default has been since sometime in Windows 2) until you the user pushes that window into one of the zones (using the mouse or a keyboard shortcut). A tiling window manager should default to that automatically without user intervention.

There's definitely plenty of overlap: Fancy Zones has some options to try to automatically remember to snap applications to given zones.