For someone that doesn’t know about this, how does a CDN help? Don’t they still have to pay for all the data downloaded even if it’s hosted on a CDN. I thought

For someone that doesn’t know about this, how does a CDN help? Don’t they still have to pay for all the data downloaded even if it’s hosted on a CDN. I thought the whole purpose of a CDN was just to make access quicker and had nothing to do with saving on bandwidth costs.