Why should I delete cookies?

The main reason for deleting cookies is to ensure your privacy.

Deleting your cookies will also delete any usernames and passwords that your browser has saved. Other people using your computer, tablet, or smartphone will no longer be able to simply sign in to your accounts. Deleting cookies will also prevent advertisers and commercial parties from monitoring your online behavior.
If you don’t delete your cookies for a long time, your computer, tablet, and smartphone could theoretically slow down as well. So, it goes without saying that you delete all cookies from time to time.

What are cookies?

Cookies are small informational files that are sent to your browser when you visit a website. These cookies, among other things, ensure that certain settings and data about you can be stored. For example, you can save your login information so that you are still signed in the next time you visit the same website. Cookies remember the contents of your shopping cart when you visit the online store. Cookies are also often needed for a website to function properly and for website visitors to feel comfortable.
One of the warnings about cookies is that it does not always specify exactly what information is monitored and collected. For example, certain cookies may provide the site administrator with information about your behavior on the site (how long and how often you have been on the site and which pages you have visited). In addition, commercial parties may use cookies to analyze your browsing behavior in order to serve targeted ads. For this reason, in some cases, the use of cookies may cause privacy issues.