There are privacy laws, such as GDPR in Europe, California's CCPA or Virginia's VCDPA in the US, and others, which regulate what businesses and organizations can do with the website users' sensitive personal data that they collect. Businesses must obtain users’ cookie consent to collect and manage users' private data before the use of cookies or similar tracking technologies. The most common way to get website users' Cookie Banner to use cookies and collect users' personal data is through a Cookie Banner.
If you have a simple website, which does not have cookies and you do not collect website users' personal data, you are not obliged to have a Cookie Banner.
However, even if you do not use cookies, you may use services by other companies on your website, such as Google AdSense or Google Analytics, which use cookies. These cookies on your website are called third-party cookies. If your website uses third-party cookies, you will need a Cookie Banner.
Check for free at CookieScript to see if your website uses cookies.
Thus, to be on the safe side to comply with the privacy laws, it is recommended to have a Cookie Banner.