Some times you need support.
For example because you have closed source and you can not use the forum. Or you want custom code or libraries. Or you just have a problem or question.
We have given free support for almost 25 years. But unfortunately this requires too much of our resources.
With a license you get 2 years of support.
After that we still will give free support but with some limitations.
You only need to buy support when instructed by support. Do not buy it in advance.
Support has nothing to do with updates.
Updates are free. Official you get 2 year of updates. In practice we do not charge for updates.