I have looked through earlier threads and I do not see a 50 50 split. I have assessed it as 70% - no lens cover and 30% - lens cover. This is backed up by the very small sample here (4!) that shows almost everyone saying no lens cover
Well, I didn't explicitly vote for using them. As long as you get good ones, then there is no reason not to use a filter to protect the front element. I also use hoods to cut down on flare.