You know... equivalent exchange makes it sound all scientific and seem like the law of conservation of energy is conserved but it really isn't. First off, printed money doesn't have innate worth but only is worth anything once the government approves that printed money. The government usually has some other thing that does have innate worth like gold or silver and theoretically, you could take your printed money to the government and get the worth of the money in gold or silver. Considering this, it would be better for him to just melt down the coins and to sell the metal instead of inflating the Japanese economy with paper money the government can't back up. Also, if he has the power of equivalent exchange, he should be able to just take the currency and turn it directly into matches.