I know trade plays a role, but it's far from the only aspect:
''At its best, it is a noble alliance of honorable and chivalrous peoples, representing all the best aspects of the First and Second Empires. And from this solid foundation, perhaps a third, even mightier Empire shall arise, providing all the peoples of Tamriel the benefits of mutual respect, vigorous trade, and reverence for the Divines.'' -Guide to the Daggerfall Covenant
''Rejoice, peoples of northwest Tamriel! Though the rest of Nirn is afflicted by war, madness, and Daedric horror, the glory and honor of the Reman Empire lives on in the Daggerfall Covenant. We remain true to the primacy of trade, the principles of freedom, and worship of the Divines.
In the face of a world of enemies, the trade powers of the Iliac Bay have formed a powerful alliance. High Rock, Hammerfell, and Orsinium stand as one, united under the rule of the High King in Wayrest. Orc and Breton craftsmanship make the alliance an economic powerhouse, and the military strength of the Orcs and Redguards make us a force to be reckoned with. Our kings join our people in longing for the return of a Tamrielic Empire, along with the economic prosperity that goes with it. There is only one way to make sure the right Emperor rules once more from the Imperial City: we must attend to it ourselves.
The current so-called "Empire of Cyrodiil" is a sham, a twisted mockery of Reman's glorious Second Empire. The charlatans who sit on the Ruby Throne openly mock the Divines and court the Lords of Oblivion, the Enemies of Man. Even the once-promising Emperor Varen fell victim to Daedric corruption, his reforms swept away by the puppet-masters of the Daedric Cabal.
The Daggerfall Covenant is the only true heir to the principles of the Second Empire. In the name of the Divines, we must conquer Cyrodiil and restore the glory of Reman's legacy. The cancerous Daedra worship that has corrupted Cyrodiil and threatens all Nirn shall be cleansed from Tamriel. We shall found the Tamriel Covenant, that all kingdoms may have a seat at the Grand Council under a new Imperial Dynasty.
Forward, soldiers of the Covenant! Freedom for all peoples in the name of the Divines! For a new Empire and a new era of law and justice!'' -True Heirs of the Emprie
''Yes, we based the Daggerfall Covenant arms and armor on classic Second Empire designs, and we're unapologetic about it. In fact, we're proud! The Covenant represents the continuing ideals of Reman's Imperium, the uncontested height of Tamrielic civilization, when everyone, even the Orcs, were included in history's greatest confederation. Insofar as we seek to restore those lost glories, we deliberately hark back to them in our designs and symbolism.'' -Crafting Motifs 26: Covenant