The quartermaster at the wheel didn't really need to see where he was going. He'd have steered based on an officer's commands to steer along a certain heading. He'd used the compass in the binnacle in front of him to keep that heading. The officers would have been up on the quarterdeck (the deck right above the wheel) and would have had a better field of view from their.

The binnacle is the large box you can see in the HMS Victory photo. The small chimney coming out of the top is for a lantern that illuminates the compass face at night.

Why do this? With the wheel belowdecks, the quartermaster is protected from inclement weather and enemy snipers. It also gives the wheel some protection, which makes it less likely for the wheel to be destroyed by enemy cannon fire.