But real world freighters can tie up alongside a dock for loading/unloading. A starship freighter may not be able to do that, depending on whether or not there is a highport, and whether the size of the ship makes landing planetside impossible or dangerous.
A 500 ton is going to be made to land at a downport unless designed for a specific route where it's not needed. Just like IRL, ships don't dock in places where its dangerous. They don't carry their own craft.