Conditioning Finishers are designed to give you a little extra aerobic and muscular endurance work at the end of a workout. This is to balance out your training and create a more versatile athlete. Added benefits can include a cool down for your muscles and extra calories burned. They are entirely optional but don't require a lot of extra work. They are short in duration, averaging about 3-5 minutes.
As an alternative, you can choose any type of cardio machine or activity you'd like.