Persistent cookie is a cookie which is permanently stored on user’s computer in a cookie file. They are used for tracking the user information of the users who are browsing from a very long time.
They also have the drawbacks of being unsecure, as user can see the cookies which are saved on the computer.

“A persistent cookie is a cookie which is stored in a cookie file permanently on the browser’s computer. By default, cookies are created as temporary cookies which stored only in the browser’s memory.
When the browser is closed, temporary cookies will be erased. You should decide when to use temporary cookies and when to use persistent cookies based on their differences:
*Temporary cookies can not be used for tracking long-term information.
*Persistent cookies can be used for tracking long-term information.
*Temporary cookies are safer because no programs other than the browser can access them.
*Persistent cookies are less secure because users can open cookie files see the cookie values.”