Has anyone used these chain ball or chain barrel swivels for anything? They seem like an interesting new product, I don't recall seeing these before. 

I used a 5 link ball bearing chain swivel for fishing a 1oz spinner for salmon and pike. Sometimes when a lure is too large, a single swivel isnt enough to counteract the twist created by the huge blades. 

 

Other than huge lures that turns and rolls (spinners and spoons), I dont see the point of them.

I lost a big'un early this spring because a snap popped open. I try not to use anything between line and lure anymore. But if I had to it'd be a quality product.

I use them nearly everyday, been making my cuda tubes with them for many years.  Best product I've used for line twist.  I don't have the need to use them for anything else.