No no. It's not that the people who buy credits make less carbon for buying them. It's that the companies take up MORE carbon to offset it. It's like this:
Person A has a carbon footprint of 100
Person A gives person B money to better the environement through various means
Person B did have a carbon footprint of zero, but with the new money they now can take up enough carbon from the environment to make their footprint -100
Now person A still has a carbon footprint of 0 because they paid for it. They still produce the same amount of carbon, but they paid someone else to have a negative footprint so it's as if they did it. As long as it gets done, it doesn't matter is the mindset. ALL it is is a way to be able to say you're carbon neutral and not have to DO anything and change your lifestyle. You just write a check and you don't feel guilty anymore. You feel like you're saving the planet when you're just giving money to a good cause.