Not something new. There is a company in China www.99bill.com started email payment system 7+ years ago.

However, they failed to compete with www.alipay.com which provides free escrow service and seamless ecommerce integration.

99bill had to abandon b2c market and pick up b2b & offline market.

Email as a ATM is not 'amazingly clever' if the transactions are not protected by escrow service.