Why did jefferson believe that customs duties would create a stable economic system?

Both Jefferson and Hamilton, thought that Customs duties, would be good for the new Republic, because they would give enough profits to finance the Federal government, and it was easy to establish this law because there were rivers and costs that crossed several states, so these states could not collect their own taxes for sharing water. So only the Federal government could charge for the traffic of goods and ships through the waters of the new Republic. Since tariff revenues were strongly related to foreign trade, it was a crucial part of Hamilton's economic strategy.

They were busting people when they really didn't need to