Thick modular meshes in games. Why?

ilyatheartist

I've noticed it a lot in recent games like Oblivion Remastered, God of War Ragnarok, etc. The modular meshes have thickness for some reason, even if they are tileable or unique. But some games like AC: Mirage have all their meshes thin. What's exactly the point of thickness here? Example from Ragnarok 

ZacD

Thicker walls block light leaking and offer a little more flexibility if you want to nudge the meshes off the grid for some randomness or variation.
Also for newer games if they are using mesh shaders or nanite, closed meshes can cull meshes behind them better. 

HAWK12HT

^ that plus different engine and workflows. Thin (One sided meshes) or Thick (Closed meshes) both have pros n cons depending on use case.

okidoki

Maybe to make something possible like this:

Some zickzack line of four times the same element with scaling to -1 on the X-axis.. of course with "better suited" edges