If you plan on using decoys and have some good cover you don't really need one. Without decoys it can be tough to get in position if you don't have cover.
But on the flip side, they can't hurt! I love bow hunting from a pop up blind. I don't think I could draw on one without making too much movement and getting busted. And they don't notice them at all for some reason.
Also, it sounds like you'll have a group of them come in. You can pick and choose when to make a move with a bird or two, but a group is a lot of eyes.