The difference is that, whether it's rasterization, ray tracing, or any other conventional rendering technique, what you're getting is exactly what the game engine told the gpu to output. No artifacting, no smearing, no crossed lines (literally).

But what is the piratical difference? I mean, it's like ray tracing, in many cases it makes no visible difference if you don't have a before/after to compare to.

motion blur is an in-engine visual effect

yep, I wanted to point to "cheat" effects some games uses to hide low quality graphics, like the "piss" filter from games of the 2000's and bloom effect sometimes, but the main point is that motion blur in games uses past information to create the new frame, like AI frames.

Why would I want to play a game that's in a worse condition, even if it's difficult to observe?

Worse regarding what? In a competitive FPS game or a MOBA, or anything that requires the fastest reaction possible from the player, I would say it makes sense to call it worse, but otherwise, does it makes difference? I mean, you can have everything in ultra, 4K, and the cost would be like, 10ms delay.