When adding a contact person to a company's listing, you have the option of restricting which documents are sent to them by email or not.
For example, when sending an invoice, it would be good if it were not sent to all the contact persons linked to the company, but only to those who are qualified to receive this type of document, and then perhaps another contact person will receive copies of the sales orders and not the invoices
A kind of management of roles and permissions, but client-facing.