Zend certified PHP/Magento developer

Connecting multiple monitors to PC or laptop: Graphic card outputs vs docking station

Is there a difference between connecting external monitor directly to graphic card outputs and connecting the external monitors to docking station?

I read that new docking stations which uses USB 3 Thunderbolt technology do use in full capacity internal graphic card capabilities. But why do then graphic cards have more outputs if we can just use the docking station instead and we have the same results?

If we want to use full GPU power, resolution etc with the monitors that we connect with, which option should we use? Directly connect to GPU output or connect to the docking station?