Pretty much any kind of chain, cable, etc is just to deter lazy thieves. A battery grinder with a cutting wheel on it will take care of anything metal in just a few seconds.
Couple a good cable lock with a screaming loud alarm and you stand a chance of scaring them off or better yet catching them in the act. Just wait until they are a few steps down the road before you uncork the bird shot so you don't hit your bike.
