Most videos and books I have seen show techniques for chain whips about twice as long. With the shorter chain they go much much faster. This makes them extremely dangerous, but clearly this would add to their effectiveness. Historically, chain whips were easily concealable weapons for self-defense. I don't think police or the military used them. However, I have heard stories that the guards of the Forbidden City used them because they were not supposed to spill blood. Here is another example of the type of whip you posted from Oriental Arms.
http://i77.photobucket.com/albums/j6...chain_whip.jpg
As you say this type is a bit more common.
You mentioned locking techniques, and that is definitely part of the practice, and the chain if it is authentic should work well for it. I can catch and hold a smooth steel sword breaker (bian). The chain locks and does not let go until I give it a little shake.
It is a very effective little weapon but very dangerous to practice with. I padded one end with duct tape and bubble wrap and it still makes me see stars occasionally.
Josh
Josh