It's just a way to bypass the cantillion effect and hoard the benefit of debasement for the lord. That's why he exempted the aristocracy, he had to cut them in to maintain his power.<p>So, suppose the ruler begins a debasement. You have a lot of coins. You take them into the mint and exchange them for debased coins but more coins than you had minus a cut to the king, go buy some asset that can't be debased like salt, wait and then sell it on the market after price inflation occurs. You benefit from the cantillion effect because you got the fresh minted money before prices rose to compensate.<p>Now with the extortion scheme, you lose that. The revenue goes straight to the king in the form of the tax, the king might make do with the same revenue as before, thus significantly reducing the inflation that occurs, or maybe raises his revenue to the match the cost to the economy before but now the aristocracy get nothing. To compensate, he had to exempt them or they would overthrow him, and now they get benefit in that regular people get directly fleeced, price deflation occurs but regular people don't gain purchasing power because it was their money taken from them out of circulation, but the rich people don't have that problem so their purchasing power increases.