Let's look at an example.
A wants to have a bar but he has a shipka.
B wants to have a shipka but he has a bar.
If there is no trading system, A has to buy a bar and B has to buy a shipka since they want the guns, a total of 320,000 gralats would be spent and profited by Era.
However, if there is a trading system, A can trade his shipka to B for a bar. They will both get what they want without spending any extra gralats, 0 gralat is spend, no profit is earned by Era.
Hence this is bad for the economy, meaning Era's (Eurocentre) profitability.