Let’s say you want to convert 10 BTC to ETH and the network tells you that it can give you 20 ETH currently. But the network may receive many more requests while you’re swapping and sending your request. These requests will change the order books, the network won’t be able to handle your 20 ETH anymore and will be able to give you 19.98 ETH only. In this case, the network will check your minimum received value. If your minimum received is lower than the amount which the network can give you, it’ll go ahead and complete your request, otherwise, your request will fail.