What is the difference between a collection and an organization?

What is the difference between a collection and an organization?

Why does Bitwarden have both?

When adding to an organization, Bitwarden’s web vault also asks if you want to add to a collection. Why?

Have you seen these articles?

https://help.bitwarden.com/article/what-is-an-organization/
https://help.bitwarden.com/article/collections/