[OJFord]

Because I don't want some ugly thing strapped to my window?

Because I want to let more light in?

Because things flying in is approximately not a problem anyway?

Seems perfectly fathomable to me.

(I live in London, occasionally a fly will come in and chill out for a bit before sodding off again.. fine? I've never had a wasp inside even. Our mosquitoes will extremely rarely give you anything nasty. Moths that would fly in aren't the fabric-eating kind. Even leaving aside the other issues, there's no reason to, it wouldn't be worth my time or money to buy them/fit them/have them fitted. I've spent longer writing this comment than being irritated by anything flying in through my windows.)