The new data (there is a great book titled The First 20 Minutes: Suprising Science Reveals How We Can Exercise Better, Train Smater and Live Longer by Gretchen Reynolds) is suggesting that these types of workouts may just be the answer to those who do not have a lot of time to workout. Because high intensity interval training burns a higher percentage of calories in a shorter period time compared to steady state activity, many exercises find it easier to be consistent with their workouts. But the research is not as convincing when it comes to EPOC (excessive post-exercise oxygen consumption) and how many calories one continues to expend for the time after the activity is complete.
That being said, remember it's calories burn that counts...we are consistently in the fat burning zone...fat is the primary source of fuel for us when we are doing the most mundane activities, however, sitting on the couch, sleeping and playing on the computer do not burn a lot of calories.
I hope this helps!