What are the threats for financial system from bitcoin?
The financial system for bitcoin are:
Decentralization; because of this nature or characteristic no single country or individual can control bitcoin it has live of it own.
Low fees; because of high fee charge by western union money transfer and moneygram etc. Bitcoin financial system come to resolve this by offer low fees on transactions.
That strength of bitcoin has never threaten the current financial system under a centralized system controlled by the government, in fact they are interested with the blockchain technology and they will probably gonna copy it. Even how good that system is, there is no one that will replace the government as they are the most powerful in this world and they run our countries. So, let's not think bitcoin will change the world because of its strength and it will never happen.