Comment by Bonooru

Optimal isn't the right way to think about it. It's a tradeoff. Hub-and-spoke is usually better at getting you to your destination in less absolute time given the same number of total flights since you can have more frequent "shuttle flights" that travel to the hub, exchange goods/passengers, and shuttle back. Point-to-point on the other hand, is better for minimizing travel time since you go directly to the destination.