>>11859542
It's both mouse movement and mouse turning.

The former is great for Wolfenstein 3D because all terrain is flat, in consistent increments, and there's no acceleration or deceleration, however it's complete shit for Doom, where there's acceleration and deceleration, and terrain can have all sorts of variety and even hazards.
Hence, it's been common for a very long time to disable the mouse movement one way or another for Doom, to get only the clean mouse turning, then moving with keyboard input.

>>11859493
Yep. Seriously though, the mouse in Wolfenstein 3D is so stupidly fucking fast and smooth, the simpler environments and movement means you can fully exploit the movement precision potential of mouse input in a way you couldn't with more advanced first person shooters. It's one of the reasons I'm fond of the game even though it mostly got outclassed by later titles.

You'll want that advantage too, because most of the enemies in the game are hitscanners, some which are complete bastards.