For us, the API Kashflow has with Paypal is integral to our accounting and makes the whole process so much easier. With stripe becoming one of the worlds biggest platforms for processing card payments (hell, the 26 year old who started it is now in the top 50 rich list of the world, says it all!) having a similar integration would be literally the best thing for many businesses that use both.
I would happily even pay a higher subscription fee with Kashflow for that!! ;)