While the questions are general, I actually like them because they're all relevant and hard to answer definitively.
1. I think that the global economy influences Bitcoin more than Bitcoin influences the economy. Whenever there are major economic events, Bitcoin's price is affected, even though it may not suffer directly from something that has happened. In terms of examples, I'm thinking of the announcement of the pandemic and, most recently, news of high inflation rates at the end of last year in the UK, EU, the USA.
2. 'One day' is too broad because of course the world will change a lot in, like, hundreds of years (if humanity is still there and still developing rather than living in a collapsed post-civilizational period), and if the digital trend sticks, Bitcoin or something similar can replace fiat. But I don't think that traditional currencies will lose global dominance within our lifetimes, even though I believe Bitcoin can become a pretty strong alternative.
3. Bitcoin has the potential to replace banks, but I don't think it will actually happen within our lifetimes. Many people are too used to banks and prefer it when there's a whole system of accountability and hierarchy. It gives an illusion of safety.