I have used them. Their biggest use is for trolling worm harnesses. I have used them with cranks but I personally prefer snap weights/ guppys for adding weight to my cranks.
For my harnesses I terminate with a micro swivel. The bead weights clip system is too large in diameter to be used with my micro swivels. I use the "Red Nek Outfutters" weights. Great terminal tackle and made in Ohio.
http://www.rednekoutfitters.com/