they can hide and it is definately a good idea to get it done.. price for me =free but i think they are like 40$ or so... they only take 15 minutes but those guys like to take an hour so you dont think you're getting ripped off. anyway they will hide the actual cracks... BUT.. on impact a rock will leave a small circular rough area that no binding compound can hide.. so there will always be an ugly little rough looking mark. also if you see a guy get inside and use a lighter or small torch to the inside of your windshield.. tell him to get the hell away form your car, all it needs is a little thumb action inside and that is very sufficient. the autoglass business is full of scammers so just be careful.