The thing about either a bush in a bag or a ghillie in the right cover being nothing new for game to notice, it is that when bowhunters put in structural things like a blind or a tree stand they tend to hunt from them when on any given day certain adjustments to the plan could be an advantage. If all one is prepared to do is sit in a blind and something happens like a wind change or other people come through your area, your hunt is shot. I have gotten deer because I elected to change locations. It is quite easy to have several natural spots to blend into prepared ahead of time and still not have to worry about invaders or thieves, as is a constant problem on Iowa land, public or private.