So you think that someone who's capable of building a system like this, has somehow missed the fact that you should store passwords safely? Nah, I don't buy that.

I do. You do an online tutorial, and together with bits of code from Stack Overflow you can tie together APIs, including payment processing APIs relatively easily into what you want. You don't read the documentation, you just google till you get the code you want from SO, so any warnings in there are lost. Your boss is on your back about it and you're on your 4th straight 20 hour day, so you just do whatever to get the result your boss requires.