Your child is not going to use the play yard at all times, so it is an important feature if the play yard can be easily bundled up, stored away and set up. With a small kid tugging at you and trailing your steps, you won't have much time to spare while attempting to set up the play yard. They need to be easily foldable, preferably with one hand, so that it only takes a minute.
A play yard which can be folded and carried is also good for travelling. If you are always on the road, you can carry the play yard with you so that your kid will always have a place to play and sleep in, no matter where you are. Whether you are sleeping in a motel or visiting family and friends, you'll have everything your child needs at hand with a portable play yard.