We redesigned Juicer at a certain point, and on the "edit payment settings" page our designer added a list of "past invoices" so that our users could automatically see a history of all the past payments they had made to us.
Occasionally we would get requests from customers to send them old invoices as they had lost them. We thought it would be much easier if we just allowed the customers to do that themselves. Of course, Stripe has no such functionality.
Fortunately we already had the invoice data in Payote, we just had to build a widget to allow customers to view their own invoice data, and for products to be able to embed it in their site.
We also figured we'd give customers the ability to customize their own invoices, so we wouldn't even have to handle the requests to add VAT lines; customers could do it themselves through the widget.