That's basically just a Z87.1-2020 lens. Any lens made to the standard should protect against impacts. It's technically bullet-resistant, in that it's a polycarbonate lens, but stopping birdshot ain't that remarkable.

The reason you might wear them while shooting is to prevent a stray piece of brass from going into your eye, or spall from hitting a steel target. (E.g., the copper jacket peels off the bullet and comes back towards the shooter as shrapnel. The risk of spall is very low past about 10y with pistol targets.)