Greece is not monetarily sovereign, so they cannot create their own money. They are analogous to a U.S. state. And Argentina had a lot of foreign debt, and you can't just create foreign currency. So those two are poor points of comparison. As was your own checking account.
A better analogy might be if you had an apple orchard and it produced an infinite amount of apples; the apples don't cost you anything, but it would be unwise to eat too many. It would also be unwise (for the economy in general) to attempt to sell an infinite number of apples. But could people (and the economy) benefit from some increase in the number of apples you sell? They very likely could.
A nation's economic strength is in their ability to produce - factories, knowledge, labor, materials, energy, etc. If you have these resources (especially labor) sitting idle for lack of demand, then your economy isn't functioning as well as it could be. If you could spur more production with some of your infinite supply of apples, you could create jobs in the process, at no real cost. Sure, there would be more apples in the economy, but there would also be more people working, and more production. So you have to balance the (obviously) good (more jobs, more production) against the (possibly?) bad - whatever negative effects more apples might have on the economy.