A difference between googles and a windshield is:
Goggles will protect you from the wind, but a windshield won’t.
A windshield will protect you from the wind, but goggles won't.
A windshield will keep your eyes from watering better than goggles.
Googles will protect your eyes from the wind, but most windshields will not. A windshield is not an adequate substitute for goggles or a face shield.