Earlier quoted context omitted.
Doing just payments is a really low margin industry, and the larger the contract you are after, the lower the margins. Therefore, it makes a lot of sense to try to sign up startups, as their growth is your growth. And to win in the startup market, you don't win by lowest costs, but by how much generic work you can save them. Cut their headaches, and they'll be happy giving you a wider cut. Thus, a million little acqu…
AI is making it a low-moat industry too. It's a lot quicker to build some API docs, a behavior tracking JavaScript library, and some fraud detection, with LLMs.
Fraud detection is really, really, really, really hard so I would probably stick with someone like Stripe for this, as they have so much data that they can do a really good job.
And fundamentally, the moat for Stripe isn't just the front-end APIs, it's all the work that they do (and there's a lot) in connecting together financial infrastructure. Even if you could wave a magic wand and generate all the code Stripe has (which you can't, currently) then you'd still need to build out all the partnerships, which is a lot of work.
Disclaimer: former Stripe (though only a tourist), still hold some of their shares.