Until now, a client's brand was paid for by whoever built it, and the cost had to find its way onto the studio's own invoice. Now you can send the client a link and let them pay for it themselves.
In the publish dialog, say the brand is a client's and copy the client pay link underneath. Your client opens it, sees whose guidelines these are and who built them, and pays as a business. Their company name goes on the invoice, and their VAT ID too if they have one, and Stripe sends the invoice to them.
Paying doesn't publish anything. The brand is paid for on your account, you get an email with the button to publish, and it goes live when you say so. A link works for 30 days, and copying a new one switches the old one off.