Having worked on web apps that processed online payments before and after Stripe I totally agree, this was an area of real pain that became suddenly extremely simple because of Stripe. The alternatives were terrible–100 page Word docs of SOAP API docs for Authorize.net, massive PCI compliance requirement specifications, horrible legacy merchant services businesses.

On the other hand, I operate an app that talks to (and logs prompts/meters costs) to many different LLM API providers, and I do not consider it painful at all. I have an AI agent to deal with any integration quirks, if needed. Mostly they provide OpenAI-compatible APIs anyhow. It's basically a no-brainer to go direct with the providers and save 5%, the great majority of the cost of an AI-powered app is no longer dev time implementing the integration, it's the tokens themselves.