Reward points amount do not become available for use until 1 Day days after your order is delivered to you.
Please note that Reward points amount remain pending in case the order is cancelled or returned. Pending Reward points amount cannot be used as a payment method.
Once the Reward points amount become available (=Total Reward points amount earned - Reward points amount used - Reward points amount pending), you can use them like cash to pay for any purchases.