It’s unreliable in a retail environment, which is where I’ve seen it used first hand. The customer pays from Aqua. It shows on their end that the transaction was completed and their balance is reduced. The merchant doesn’t receive the payment and the invoice eventually expires. Meanwhile the customer and the merchant are left staring at each other awkwardly while they try to figure out why “bitcoin is broken.” The funds from the failed transaction apparently return back to the sender, but it can take up to 24 hours.