At Uber’s scale, sure, but for smaller companies you have to understand that before Stripe you needed to get your own merchant account and that meant dealing with a bank. That’s one. You also had to deal with a payment gateway, which was pretty horrible before Braintree, and Stripe was another step function, that’s two. The processors are the middleman, and here there is all kinds of details and clever ways fees are sliced. Ubers of the world have the scale to invest in optimizing this but companies smaller than <500 generally don’t and an integrated solution like Stripe just solves a lot of headaches even if it more expensive in the end. Having the expertise to even understand how to optimize payment commissions is non-trivial.