Have you ever spent some time with a coach or trainer who put you through grueling workouts? For many of us, the answer is yes. While getting a good sweat in can feel great, if you have specific goals you want to reach, then you might need a more structured approach.
The fitness world is an interesting world because everyone has their own philosophies and their own needs. When you take a group exercise class, your goals are probably different than the person next to you.
One thing is for sure, you end up coming out of any training session sweaty and exhausted.
If your overall goal is to get into better shape, then this approach can work very well for you. But if you want to try and compete in some fitness events, such as Crossfit, then you will need a more structured approach.