it's a perfect way to take my young sons hunting with me.
I'll agree with that. That's the best use for them.
I use them because I love the challenge of getting a deer within bowrange on the ground. I don't know about allowing more movement though. It's very tough to get to full draw on a mature buck from the ground without him busting you.
It's also a good option for areas that simply have no trees for a stand. I don't mind them, but I think the odds are better 20 feet in the air.