The condition states automatic fail on perception checks for sight or -4 if sight is primary sense. So far so good.
However, how does that translate in the ability to fight?
Well, you'd need to seek with imprecise senses to figure out where, exactly, things are, which takes up actions.
And if you do figure out where an enemy is, they're still Hidden from you, so you're flat footed to them and have to make a DC 11 flat check to attack them.
The condition states automatic fail on perception checks for sight or -4 if sight is primary sense. So far so good.
However, how does that translate in the ability to fight?
Everything you fight is going to be Undetected unless you make a perception check with that -4 against any stealth checks they're attempting to make them Hidden. So you either attack random squares and hope someone is there or if they're Hidden you attack the correct square but have a hefty flat check to make even if you hit their AC.
Makes sense! Thanks!