Having a gun in your house is having a weapon that is just sitting around waiting for someone to use it. Criminals themselves do not get a license for a gun to commit a crime, usually it is a gun stolen in a home break in, or one owned by a relative. If a person has a gun for self protection it will more than likely never have to be used, but once you have one you have put one more gun into the possible hands of a criminal.
Yes, I think gun buybacks do help stop some violence some of the time. If you have a gun and want to turn it in for money, you must not really need the gun. Having a gun in the first place is a recipe for violence and disaster, so having the buy backs is a great idea.
Just like they saw in Australia, criminals didn't turn in their guns. After the gun ban was implemented in Australia gun crime went up. No matter how hopeful we may be to reduce gun crime, gun buybacks don't seem to be the answer at all. No matter what, criminals will not obey laws, especially gun laws, so crime will not go down with a buyback.
While gun buybacks may stop the occasional accident in someone's home, overall, they are not going to have a big impact on gun violence. Your average murderer or rapist is not going to participate in a gun buyback program. Any gun death that is averted is a good thing, but it's foolish to think that buybacks will stop gun crime.
Gun buybacks do very little to actually stop gun violence. This is because those responsible for gun violence, i.e. violent criminals, are the least likely to turn in their guns. Guns are their tools of their trade and if they were to get rid of one for some reason, they would sell it on the street for much more money. Those who do turn in their guns during buybacks tend to be average citizens with old or defective firearms that haven't been used in years. As a result, gun buybacks are mostly ineffective.