Before the day becomes hot or at sundown, they can be just the thing to wet an area where the ground is moist enough but the heat of the day caused plants to fade and have a difficult time taking water up through the stems.
The wobbler itself is useless without a stand so if you decide to get one, be sure to get a stand at the same time.
The stands vary in quality. The one we bought has 5 legs and can be unstable on our rocky hillside. Also, the legs had to be glued in to keep them from falling out. But, all in all, it's OK for our use, folds up easily and is light for moving around.
I saw other wobbler stands online that have 3 sturdy legs and a brace between 2 of the legs - which looks more stable.
Suppliers include Gemplers at http://www.gemplers.com/product/167758/Mini-Spider-Sprinkler