For selling, instead of spending 100 USD to buy back the jEUR, and then retrieve 110 USD, the pool utilizes the jEUR to redeem the 110 USD, and then uses them to pay 100 USD to the seller, and keeps the rest. Therefore, there is no liquidity needed for selling jEUR; the maximum amount of jFIATs that can be sold is the maximum amount of jFIATs that have been minted with the pool.