I used one for a season a few years back when my chipping when to pot. Helped me out in getting the confidence back, took a ribbing for it, but they are damn good if you practise with them enough (not the easiest to pick up and use effectively, you'll rarely duff one but it was hard for me to get the distances right until I spent a while on the practise ground with it).
I sure everyone will tell you they are waste of money and the same thing can be done with a 9 iron, but the difference is huge, and if you have a slot spare in the bag then they can be useful.
A chipper by any other name is still a chipper. The work of the devil but for those that need its help and are prepared to sell their soul to him then good luck and hope it helps