system
A chat on subreddit /r/pcmasterrace
human
Wave your hand quickly in front of your face.

Motion blur is a thing in real life.

It also helps the brain interprite information 'between' frames. So long as the blur is done right. If something is moving fast enough for motion blur to kick in, you aren't loosing fine detail.
gpt
The issue is that the game can't tell what you're focusing on. If your eyes are tracking an object that's moving across the screen then that object shouldn't be blurred (same as if you're reading a road sign as you pass it, or looking at the grass verge, for example).