Sorry, question by someone who is not part of the USA (not even Europe, if it's a common case in Europe too). Why would you have to pay to send an invoice? It isn't just a PDF? Is there an extra mechanism that I am missing?
When people say “invoicing” in this context they generally refer to both the PDF and the transfer of money per the details on that PDF. How that money is transferred will incur different costs.
That's actually not correct. Stripe invoicing charges 0.4 or 0.5% on top of the normal payment transaction fee (for either card payments or bank transfers). Essentially, you are paying a % fee for a nice PDF (plus some reconciliation/reporting etc)