Along the same line of thought, there are definitely times for both.
A light strap on stand can be pretty mobile, but typically if I hang a tree-stand it'll be there for a while--as in weeks...
A pop up blind takes 5 minutes to put away and be on the move again, but one big enough to be comfortable in is going to be tough to carry quietly and agilely, not to mention you'll probably be carrying a stool or chair as well.