People use Stripe’s forms because they’re convenient. It’s not a requirement in any way. Stripe provides APIs to build everything in their provided forms so you can build the functionality into your own site easily.
You are apparently not working in eCommerce and don't seem to know how 99% of merchants work nowadays. Merchants don't integrate by calling the Stripe API. They use a platform and those integrations are built-in. The amount of merchants that are actually building their own integration to Stripe API is a very small %, and majority of them would be very large retailers that have the staff to create their own ecom platform and are PCI compliant. Small/medium retailers for the most part are not working that way.
Again, merchants don’t integrate by calling Stripe APIs directly out of convenience. It’s more convenient to use an out of the box solution. But from a technical perspective, nothing is stopping a merchant from accepting your CC details directly.
> But from a technical perspective, nothing is stopping a merchant from accepting your CC details directly.
From a technical perspective, no, nothing is stopping the merchant from asking you for a string of numbers and a month/year date, storing it, and believing that "technically" they can send it to the Stripe API to charge you.
That's when they will realise that, from a business perspective, there absolutely is something stopping them: that they literally cannot do any business whatsoever with your CC details directly, unless they are fully PCI compliant to the same level as an actual PSP.
I had a job waiting tables when I was a teenager when my co-worker got busted for writing down credit card numbers and info when she took the tables' cards to charge them. Apparently she had racked up over 100 thousand in fraud over time.
