What is -- Edit >Puppet Warp in Photoshop CS6? Is it helpful tool?

it is similar to the puppet tool in after effects, basically you add to your alpha-transparent images mesh grabber which allow you to add controller points and move your image as puppet. since Photoshop is allowing2d animation and adding timeline so you need more tools to create deformable images for animating things and characters.

No doubt, puppet wrap is a vey usefull and handy featuer of photoshop, you can youse puppet wrap for band and mold your pictures, for more clarity you can gone through this link for better understanding. puppet wrap

Yes, Its Very good Tool in Photoshop. when you want to band your picture, you can use it by specific points in this tool. 

For Example if you want to band leg of an elephant then select it by puppet wrap tool and give point on it.then use this points to move leg.

puppet Warp feature can be extremely useful if you need to make minor adjustments to your photos. or another design you make better for using puppet warp tool.

It's an adjustment tool that is very useful for images, fonts or GIF format that can be edited in photoshop...

puppet wrap tool is the most advanced wrap tool which is used to wrap the particular part of the image & text for example you can apply wrap for the one finger of the hand image