That's an illogical statement. In the real world, nations (including island nations) often have needs that are greater than their cash on hand.
For example, what if your people need an international airport to run their businesses in order to make money? In this case they need money to pay the taxes for an airport, but they need an airport to make money. How would you solve problem without borrowing money? Borrowing money is a good solution (particularly if you can do it at a low interest rate), it will raise the incomes of your people meaning that in the long run it will pay for itself. By not borrowing money, you condemn your people to poverty.
Of course that is only one example, there are many other examples when a nation would need to go into debt. You might need a hospital. A hospital will easily be used for 30 years or more, but if you need one now you can't wait for these 30 years of taxes. Are you going to let people suffer and die without a hospital until you have 30 years worth of savings (which will take 30 years)?
Or are you assuming that somehow your nation has magic powers to generate revenue with zero investment in infrastructure, education or public health?
Of course a magical nation would never need to borrow money.