The fact that Bitcoin has marketcap over $1T is not making it important to global economy. Was $1T actually invested in it? No, it's just the result of trading at high price multiplied by total supply. Bitcoin could crash to zero tomorrow and it won't affect the global economy because there's like 200-300 million people who own some Bitcoin, and only some percentage of them would be ruined financially if that happens.

But don't worry about it, Bitcoin can't be taken over easily, because it's a global network of thousands of computers and mining has proof of work, which makes it very expensive to take over.