I don't believe that attacks are good. They make people nervous and can cause som.e price-fall. Sometimes hacker attacks may succeed (like it was with Zaif exchange) and a loooot of people will lose their money.
Op only tell us there are some positive thing about cyber attacks, people sometime only see from 1 side and not in 2 side of a problem. A lot of thing in this world will have positive and negative impact and we can't deny that.