The choice of Document Sending Profile should be done on Document (Report) Level and not only on Global or Customer/Vendor level.
The daily life problem is, that for the same customer, the Delivery Note is to be printed to the printer in the warehouse but the Invoice should be sent by e-mail.
In the current standard, it is only possible to choose either "Printer" or "Mail" for the Customer, meaning all documents (Reports) are handled the same way.
The Document Sending Profile could be added to the global “Report Selection – (Sales/Purch.)” -table and the “Document Layouts” on Customer and Vendor.