Depth of field is reducing the optical information on the screen / view,
and why reduce the feedback for the player in a fast egoshooter?
Just to write the feature on the package?

A filmmaker, staging a large battle would try to avoid this depthblurr,
if the scene should show the whole battle, and not just the protagonist
and antagonist in closecombat.

This blur should at least not accur in the range where the player interact with
the enviorment. If it is just for some backroundstuff, it is ok.
But it should not blurr close items and structures then,
and the focus-distance of the blurr should be constant.