Apart from their nefarious reputation for being exploited, cookies used to benefit your web experience too. Your browser can hold your ‘session’ on any website and keep you logged in, but cookies let you stay logged in between sessions. So for a site that you liked to stay logged in on, cookies could help you from the annoyance of having to log in every time you returned.
I have long since broke my lazy habit of staying logged into websites and have more recently adopted browser settings that deny cookies and delete them after closing.
There are super cookies as well that are stored even when you delete regular cookies.
How to:
https://www.technadu.com/how-to-clear-cookies-and-supercookies/100145/
How to delete cookies:
https://us.norton.com/internetsecurity-privacy-how-to-clear-cookies.html
https://www.ccleaner.com/knowledge/how-to-clear-cookies-from-your-browser