Wormholes first seems to be relative of black holes and hence destructive. But they are not. It is a curvature bent in space-time continuum joining one point in space-time with other. As they are curvatures in space-time, they can help us traveling in space without actually traveling i.e. teleporting. The second thing is that it will help us in traveling in time.
Now the question arises how will you get one???
You might be aware of String theory(after modifications:M-theory). At the Planck's level of space-time there exists many of these worm holes. But they are so small for human to travel through them. Today scientists are finding a way to enlarge them. Even if find a pretty big one we don't know how to travel through that? Because this in not as easy as it seems. We are talking about teleportation and time-traveling which will require bending of space-time which luckily is not hard with wormholes. But bending space-time will be an energetic and violent process and to control them to travel in space-time it will be necessary to harness and control the wormhole and hence to control the huge amount of energy probably equivalent to energy released by several nuclear fusion reactor which is being used by the wormholes to bend the space-time and we, now, can't even control the energy released during the fusion of one H- atom. So it will be pretty hard for us now. A little mistake in controlling the wormhole will turn the earth into ashes. But the only consequence is not controlling it. The main problem is using it. Teleportation is pretty safe unless you end up near a star. But time- traveling is something which can create paradoxes. Altering a small event will change the future and the worst thing is that only the traveler will know the changes in the new one.
So if you find a wormhole don't disturb it untill you know the way to control it or you will become the reason for the end of the earth.
