Until someone makes progress on creating a force field of sorts that wraps around you and your dog and prevents him from running away on walks, you're stuck with using a leash. You might like the look of chain leashes, and you probably like their cost in comparison to other types, but they can lead to problems. For leash biters, though, they're often a great deterrent.
Maybe with future technology, chain leashes won't be so heavy and burdensome, but as it stands, they weigh significantly more than other types of leashes. Some dogs hate hauling around hefty leashes. This mostly applies to puppies and small breeds. Puppies tend to be odd little creatures and when they're first getting used to walking on a leash, they prefer not feeling it at all. Something weighing them down often causes the youngsters to plop down on their butts and refuse to move. A heavy leash can also mean discomfort for you if you have multiple dogs to walk and you're not using a coupler.
Some dogs, puppies especially, think of their leash as a chew toy. If your puppy gnaws on his leash like some type of fanatic who loves the taste of leather or nylon, a chain leash can put a quick stop to the annoying habit. The moment most canines bite down on metal, they open their mouth to spit the nastiness out. If a chain leash doesn't prevent your pal's biting habits, switch to a different leash and opt for another strategy to stop his behavior. Constant biting at chain links can damage his teeth.
If your dog pulls or reacts aggressively or fearfully when he spots people, dogs or other animals, forgo the idea of a chain leash, at least until he reacts calmly on walks. Chain leashes do not provide the same level of control as nylon and leather leashes. If your pup pulls or lunges toward something and you need to rectify the situation in short order, grabbing his leash close to his collar gives you the most control. It enables you to better restrain him and, if need be, lead him away. You cannot grab the chain links on a chain leash if you'd like to keep the skin on your palms. Even flexible leashes have a piece of nylon to grab at the base of the leash.
When shopping for a chain leash, make sure the leash has a comfortable grip -- typically made of nylon, leather or foam -- that you can hold onto. Bare chain leashes are not at all good options, even for dogs who don't pull on walks. Opt for a 4- or 6-foot leash. Even well-behaved pups sometimes pull a little at things that catch their attention. The shorter the leash, the more control you have. Shorter chain leashes are also typically lighter. Always look at the recommended size before making your purchase. While some chain leashes bill themselves as one-size-fits-all, others are made for specific sizes in mind. Buy a leash that's too small for your pup and he could snap it.