How is having a common currency in the European union beneficial?

It makes it impossible for a member countries to suffer economically.
It allows each government to make its own policy regarding currency.
It allows the worth of the currency to change depending on the country.
It allows for easier trading and eliminates the need to exchange currency.

It promotes economic stability and growth within the EU.

It reduces transaction costs and eliminates exchange rate fluctuations.
It enhances price transparency and facilitates cross-border investment and trade.
It promotes a sense of unity and integration among EU member countries.