The snout and teeth are, not only a weapon for a dog, but a tool for cleaning paws and other parts of its body. They chew and groom during socialization with other dogs, and it is in their nature to chew an object, since it is a part of the game as well, but also to strengthen their jaw and clean their teeth. Chewing, in that sense, represents both physical and intellectual challenge, while it uneases the pain when cubs change their primary teeth.
It is up to us to limit their natural urge to what is allowed and what is not allowed to chew or eat. It can be toys for dogs, old gloves, a branch... It is important that they are safe and, in case they swallow smaller part, there is no medical consequence.
If a dog, whether inside or outside, uncontrollably chews, eats or hoovers anything that comes along: it is behavioural problem that can develop into other kinds of unwanted behaviour. Besides that, it can be harmful to the dog.
Very often they will swallow something big and dangerous to their stomach and bowels, such as plastic, cigarette butts or something even more dangerous: to cut the cable and get electric shock. Usually, the owner's response to such behaviour is that the dog just likes chewing and eating and that it is what it is, ignoring the seriousness of the problem.