+1.

More important if you race, or do training rides where you're in a pack (as oppossed to a paceline) and sometimes don't have the option to move laterlally.

Even without racing, there are still times it's handy; pothole on a narrow shoulder, and traffic prevents you moving laterally, wet railroad track that cuts across the road on a diagonal, and traffic doesn't allow you taking it at a 90 degree angle.

Done right, hopping is going to be both safer, and easier on your wheels than the alternative in a number of cases.