As per GDPR (General Data Protection Regulation) Rule.

to fulfill the specific requirement site-builders must display a banner to inform people about the use of cookies.
As per rule "you must ask user permission if you want to store cookies on the browser of a European (EU) citizen. you won’t be able to collect information from users who don’t accept the use of cookies by their web browsers. That is the law."

According to the GDPR user can withdraw their consent too.

If you want to display the Cookie Compliance Banner only in European countries, you will have to install the smart_ip module .