Notably, these cards require online funds verification and settlement for every transaction. Some cards you might get through a bank or major card company may not, for convenience sake. But these cards do, for the obvious reason.
They're essentially pre-paid cards that load instantly (at the point of transaction) from a larger balance the dev/company controls.
There are even multiple APIs for creating card issuing APIs, checking account issuing APIs, etc. These have itemized pricing that looks more like AWS/GC/Azure pricing and are more complicated to use, in the same way AWS is more complicated than running everything on a single Digital ocean droplet.