I have never seen evidence that more commercial resources would increase the likelihood of someone agreeing to a trade agreement. The diplomatic system is very veiled here. I have seen that groups with 200-plus relationships are opposed to profitable trade for them and that groups with 5-strong relationships accept the same trade. However, remember that you have limited trade agreements that can be increased by a number of means – and you must also be connected to their lands/have trade-related ports. On the left (on your side), the interface shows you how much you earn with the trade and resources you export to your trading partner. The right side shows how much money they earn and what resources you import from them. The last diplomatic option, just as important, is trade. Trade is divided into several parts. You can send or receive a certain amount of gold from another fraction as a one-time or long-term payment.
This is similar to food – you can send a certain amount of food to another fraction during X number of rounds, or get it from another fraction. The third option is to exchange items – weapons, armor, mounts, supports or accessories – in exchange for the influence, gold or oppression of other diplomatic options. As a master of the art of commerce, Kong Rong has two unique ways to further increase its commercial influence: maintaining a high population and a unique agreement in diplomacy that further enhances the strength of its trade relations network. When a trade agreement is concluded, the share of the total profit is distributed according to the commercial value of the two warlords. For example, if Warlord, with a commercial influence value of 100, enters into an agreement with a warlor with a market value of 200, the second warlor will do double the benefit of the train agreement compared to the first warlord. Everyone benefits, but the most influential trader gets the best deal! Note: The Tomb Kings are the only faction that actually uses resources for their mortuary cult mechanics (Edit: a similar mechanic called forgery has been added to the dwarves in Warhammer 2 only since this response was originally published). For all other groups, resources only increase the value of trade agreements. So you`re generally right to think that these resources are not actually used by the trading partner, but not in this particular example.