You're wrong. Elliott didn't give Argentina anything that it wants returned. The company just waited for the moment to buy bonds for almost nothing from the real creditors with the bet "if we get it on court, we win big, if we lose, we lose a little."

From the same article:

"Legal filings indicate that the face value of its Argentine government bonds was around $170 million, but the firm most likely acquired many of them for much less than that. Elliott and other investors are now seeking more than $1.5 billion, which includes years of unpaid interest."

Elliott just blackmails Argentina to extract many times more than it would otherwise be reasonable (without the blackmail condition).