I'm going to guess that the most likely reason is that a terrible progranmer or manager was behind the decision of making the customer do the extra work instead

I'm going to guess that the most likely reason is that a terrible progranmer or manager was behind the decision of making the customer do the extra work instead of the development team spending a little more time to parse it. I doubt there's a reasonable explanation as to why a CC field can't contain dashes or spaces. I'd love to hear one but I doubt there is one.