They probably couldn't find a designer in SF that charged LESS than the designer in Germany. A company that doesn't pay invoices tends to go for the cheapest option.
Because cheaper designers and developers are the ones that underrate themselves, usually because they're newer to the business and think it's pretty cool that they can get anything for what they're doing.
Which means they're less likely to be jaded, have up-front fees, verbose contracts and installation payments. As is obvious, in this case, when he talks about having 6 months of unpaid work.