We don't recommend sending payments from cryptocurrency exchanges/web wallets because transactions from exchanges often get sent after a significant delay. Sometimes, the exchange subtracts a fee from the sent amount. As a result, transactions arrive too late (when the invoice has already expired), and/or an insufficient amount is sent (so the invoice is underpaid, and you need to send the remainder in another transaction). That's why we recommend using one of many open-source wallets, where the sender controls the exact amount sent and when the transaction is sent.

Furthermore, you do not control your bitcoins when using a web wallet, so you introduce counterparty risk and thus negate one of the main benefits of cryptocurrencies - to be in complete control of your own money.

You can find our recommended wallets here.