Among other benefits, a Kalix paid plan:
allows one to have more than one project, and
for those projects to be long-lived.
In contrast, one can have only a single trial project, and that will eventually run out of resources.
A Kalix Organization is created for each paid plan.
New projects should be associated with the organization. Relevant billing data is collected at the organization level and is related to the resource usage of all the projects within that organization.
Organizations are given access to particular regions, and new projects for the organization must be created in one of these regions. Regions are associated with a particular cloud provider and a particular geographic region. See more on this in the regions page for organizations.
An organization has user members. Those users can then be granted various privileges with respect to projects under that organization. See more about this on the managing organization members page.