It's not for the sake of performance, but actually how the game runs on real hardware. The only problem is, the game was designed to run at 640x480 so on real hardware that depth of field blur wasn't incredibly noticeable. Now you can have a super high resolution and it makes the effect far more viewable and very ugly.
I believe the "fix" to remove it is to simply use "Copy EFB to system RAM" instead of "Copy EFB to GL Texture" in the advanced options of the graphics plugins.
I believe the "fix" to remove it is to simply use "Copy EFB to system RAM" instead of "Copy EFB to GL Texture" in the advanced options of the graphics plugins.
