That's kinda like saying you'll lose weight from just lifting weights. We all know what you're eatting counts for most of how much you'll lose and doing something aerobic will help burn more calories. The article didn't say what those people were eatting.
I've actually had good results with pilates and some yoga. My abs and thighs are more toned and firm, which were my goals. If I do too much weight training with my legs they get bulky.
The article does say:
The researchers found that, on average, a person weighing 75 kilograms (or 165 pounds) burns 480 calories per hour from an advanced workout, 390 calories per hour from an intermediate routine, and 276 calories for every hour of a basic Pilates workout.
It does burn calories, about the same as a weight training workout. I weigh about 130, so I'm guessing I burn about 200-400 calories doing an hour of pilates, doesn't sound that bad to me!