Exercise tapes, live aerobics style classes, training on cardio equipment, etc are largly a waste of time. Yes, if you are totally unfit you will see improvement but you could get the same from a consistent walking program. Long term the above cardio based programs will make you weaker and hungrier. Most people use them as a misguided way of purging calories.
Wrong.
A properly done, high-intensity cardio workout improves your cardiovascular fitness in a manner that cannot be obtained by walking. (Unless you’re talking about “power walking” at a very high intensity. And even that doesn’t exercise all of your muscle groups.)