Ever hear of skinny-fat? That's where someone is at the right weight, but because they do no exercise they have NO muscle tone. It's better to exercise and not have a perfect diet than not exercise and have a perfect diet.
That's where basic fitness comes in. 10 minutes of high stress activity a day builds more muscle mass than 2 hours of low impact cardio. Or to put it another way typists don't build large muscle in there forearm but a bricklayer does because stress is far more important than duration when it comes to muscle growth.
That's not to say cardio is pointless, rather unless your trying to build stamina for some reason cardio takes a lot of time for little short term benefit.
But the dirty little secret is burning calories though exercise is basically a waste of time compared to simply eating less and it takes vary little to get basic fitness. So assuming your diet is reasonable you can look like someone that spends 2 hours a day in the working out by doing to same basic routine without the cardio.