Meaning of "leverage"?

It means "raises it into position(the value of the port)". It is slightly awkward usage, but that's fine since the terms of reference are somewhat abstractions in themselves. Imagine a model of the port as representative of its worth . Now imagine you getting firm footing and using a long sturdy piece of lumber (a board) to act as a lever. You get good leverage because of firm footing and because you use a sturdy board, both to get the model into the modular space for its worth to be fully seen. The usage seems better once you understand how the writer was picturing what he meant. In this case, it was illuminating.