Like with everything in business and engineering, there's a tradeoff. My previous employer used Adyen as major payment provider (for quite some time, too). Their cost structure is sensible, the payment methods they support are convenient[ß], and their functionality is reasonably solid even in the edge cases. But everyone who maintained the payment service kept cursing Adyen for their awful APIs. The python runtime powering the old system had to carry an unmaintainable and effectively abandoned library to be able to process the Adyen payment gateway messages.

From what I understand, Stripe's main value proposition was: "how can we make this gnarly, confusing and complicated system an easy-to-use service that does NOT require the end-user to internalise the entire payment provider state transition universe?" That is obviously a valuable service, but is it valuable enough to charge an ongoing rake of nearly 300 basis points?

ß: for some weird reason people still insisted that they absolutely must be able to pay with Paypal. 2+ years of fighting cross-corporate politics + KYB and still having to stomach insanely high commissions left a properly bad taste.