Insurance still works even if insurer knows exactly how probable is given outcome and how much exactly will it cost and adjusts the fee to that. People don't insure themselves because it's a good deal. They do it because they know they won't be able to survive financial burden of some rare event that most likely won't happen but they need to be sure that in the case it happens they'll be covered. And they are willling to pay for that.

Risk is still pooled because payouts come from fees of the people that didn't (and won't) experience costly events themselves.

More information just makes the business more just and less random for insurer.