I don't think Stripe identifies as a "payment processing company". That's the category their main product exists in but as I understand it, their mission as a business is to "increase the GDP of the internet", which is why they are invested in projects like Stripe Atlas to make it easy for people to form new businesses.
Under that banner, releasing content aimed to help businesses be more successful is totally aligned with their goals.
I think it's a little bit different, Mercedes-Benz, Coca-Cola, Nike, and Apple, are all just as much lifestyle companies as they are product companies in their given verticals. The big reason they are able to charge the prices that they do, and retain the clientele that they have is due to that lifestyle image.
The cars Mercedes makes and sells are absolutely abysmal (overpriced, unreliable, expensive to operate) when viewed as transportation appliances. Yet there's a reason the company still exists and its customers didn't buy Priuses instead.
Well a higher volume of transactions benefits a payment processing company, so “increasing the GDP...” is very much what you’d expect of a payment processing company, however they choose to market themselves. Plus “making the world better/richer” is a popular SV marketing spiel, and clearly they know marketing.
Under that banner, releasing content aimed to help businesses be more successful is totally aligned with their goals.