I don't know if the destruction of the economy will destroy the economy. However, Bitcoin is playing a big role in the global market. People all over the world are now investing in this bitcoin platform.We can already see that Bitcoin Bank is now launching Bitcoin ATMs in different countries around the world.But I think the bitcoin economy will play a huge role in the market.
Bitcoin is like a knife, if we use it for good things it will be useful, but if we ignore it then one day it will hurt us, it is important for countries to immediately make rules that accept bitcoin because the marketcap and the number of bitcoin users can be greater than the economic power of one country.
Its not only with Bitcoin, its with any local currencies. Its up to how they are used. It can be used for legal things or illegal things. Since BITCOIN or another crypto currencies can not tracked, many tend to use it for illegal activities. As long as its legalized or accepted country wide, then yes, there are chances of reducing such activities.