Data access restricted by policies? How does work?

This is a quote from a Collibra page on the web:
“Organizations have a regulatory obligation to keep data secure. Giving access to a few select users defeats the purpose of the catalog, but uncontrolled access to all data by all users poses risks. When organizations enforce policies in Catalog, the right people can access the right data for the right purposes.”

Being new to Collibra, I don’t understand the true implication of the last sentence. What does “access the right data” mean? How does Collibra enforce data access with a policy, or are they simply referring to access to the data in the catalog and not data in a source? If someone could clarify and elaborate on what Collibra means by that statement, I’d appreciate it. Thanks in advance.