It seems to be getting easier to book cheap Business Class flights so why would you book with miles? (travelingformiles.com)
These rates increase to 30,000 / 60,000 miles for awards booked in premium economy, and 40,000 / 80,000 miles for business class flights. (upgradedpoints.com)
There is also real value in booking business class flights with partner airlines. (rewardexpert.com)