A dog park or exercise pen is six or eight hinged panels that form a closed ring in which you can put your dog or other types of pets for semi-supervised time, either indoors or outdoors. Dog playpens come in different sizes and are constructed of steel wire, similar to wire dog crates, plastic, or a newer emerging variety that is similar to soft dog crates.
The advantages of owning and using an exercise pen is that, just like a dog crate, they will help speed up and simplify training at home. You can always have your puppy in training close to you due to the portability of the exercise pen. You can put your puppy or dog in the playpen while others visit, which provides a good area for confinement other than the crate. The playpen provides a safe, enclosed area for a puppy or dog outside, rather than running all over the backyard. The pens are lightweight and easy to position, making them ideal for confined areas on the go. A pen area could be a good place for a recovering dog that must be confined while recovering from surgery or illness.
The disadvantages of using an exercise dog pen are caused by portability. Playpens are lightweight and portable, therefore not suitable for a large breed puppy. Most are too small for larger dogs, in which case a kennel may be more suitable. There are no anchors for these types of exercise pens. I figure you could get some U-shaped garden fillets to anchor this well enough to keep it from moving.
If you have a reserved puppy or a small breed puppy or dog, a dog playpen can be a very good alternative so you can let your dog get some exercise while you do some things around the house. These exercise pens work great for other types of small pets, such as cats, rabbits, guinea pigs, etc. Some of the newer soft sided pens come with lids to provide a completely enclosed area.