I don't want to be too cynical but it can function as a kind of elaborate PR and recruiting tool, as well as generally support the impression of the company being the Next Big Thing. As Square had to open up their finances and work on profitability, they got more focused on core product. I wonder if Stripe will follow.
I also wonder if there's something particular about payment processors.. maybe overcompensating? Is it part of the business model to kind of puff up a company around what should otherwise be a commodity-priced core service?