Comment by blairbeckwith

Their about page (particularly their mission statement) provides some color: https://stripe.com/about

Stripe hasn't been "just a payment processing company" for quite some time.

An optimistic view of this move is that it fits in well with their mission: these books could, in theory, inspire, educate, and motivate people to build or grow their businesses.

A more cynical(1) view is that this is simply more elaborate content marketing – getting Stripe's name out there to people who are interested in this content, who are overwhelmingly in Stripe's target market.

(1): Cynical in that it's less feel-good, but I don't at all mean that this is a bad thing.