Buffer really isn't the exception. They're an exception in that they've made all their data public, but my experience on both sides of the fence as someone who both runs Stripe Connect services and also manages the technology for companies who use Stripe Connect services tells me that most companies are not concerned about sharing their financials with trusted parties in exchange for a major operational benefits, whether that's analytics and reporting or automation of customer service operations.

As a Stripe Connect service operator (at http://churnbuster.io/) I've only once had someone in the onboarding process express any concern that all their financials would be available to our service, and in that case they were a developer who wanted to double check with their CEO that it was OK, which it was.

Your question really isn't for Josh, it's for Stripe with regard to the entire Stripe Connect ecosystem. Sure, some people may be really concerned about sharing financial information with a third-party service, and that's totally fine, but I'm pretty sure they're the ones missing out. Speaking now as a technology consultant, I can say that the ability to plug-and-play all sorts of different and very valuable third-party services is allowing the rest of us to build businesses in record time with minimal investment and part-time resources.