Stolen bikes

its not the material, it's the technique.

chains allow for locking to more varied objects, if you keep your chain tight and off the floor, you won't get through it in 5 seconds with wire cutters. you need bolt cutters, and the leverage of the floor and body weight to get through. take those fabric sleeves off your chain when you buy it, and chain the bike up as tight as possible.

and not only that, the technique on how to lock your bike properly, some people have the best lock money can buy and end up pointlessly lock their bike by their front wheel only, of which take a couple second to removed.