Yes, you need to have a Dierbergs Rewards Account to clip digital coupons.

Dierbergs Digital Coupons are now a part of Dierbergs Rewards! Once you have an account, scan your Dierbergs Rewards barcode (from the Dierbergs App) or type in your phone number at checkout. This will apply any digital coupons clipped through the Dierbergs App or website that match up to items you are purchasing.