Plastic engine cover-does it need to be on?

I just replaced my spark plugs and I didn't fully connect one of the plug wires to the coil so when I drove it, the Engine symbol flashed. I stopped and rechecked my work, found the loose wires, reconnected and it's fine. However, it was a pain in the butt to take the engine cover off.

My question, other than aesthetics, does the engine cover serve any other purpose?