By displaying the American Express logo at your place of business and/or on your website you signal to millions of Cardmembers worldwide that you proudly accept the Card.
Cardmembers look for the American Express "Cards Welcome" sign to find out if the Card is accepted. In fact, 49% of the Cardmembers are influenced by the American Express acceptance when deciding where to shop and dine.
So it makes good sense to display the American Express logo to bring Cardmembers into your Business. Also, allowing customers to choose their preferred payment method ensures good customer service.
All American Express promotional materials are available to Merchants free of charge.