This is true. Trump is not doing it for himself though. The US is currently embroiled in a war with China to see who will lead the world in the 2100. Part of that war is economics, part military, part diplomacy, part culture.
Cuba produces nothing worthwile. Yet it still must be made to surrender. Why? First to show that theres a penalty for going against the US. Second to show that China cannot protect you.
Iran produces oil most of which China buys. You bring Iran to yourside you control that oil. Will they stop selling to China? No. But you know that if conflict comes if Iran is on your side you can cut that oil of at any time.