Hi Rasa - there are hundreds of possible integrations out there and, speaking personally, I'm glad CB has decided to limit what it does and not gone the way of Xero who offer hundreds of integrations but with no way to easily judge & differentiate them.
As it happens the last time I looked, Receipt Bank is the biggest in the market and actually the most popular Xero add-on and so it makes sense for CB to go with it.
Having said that, per the Roadmap published a few weeks back https://www.clearbooks.co.uk/2016/05/27/product-roadmap-may-2016/ further integrations are being planned, starting with the often requested Stripe and so I'm sure people will get the chance to vote on others.