HTTP request method
There are several ways in which a visitor can arrive at your website. The GET method indicates that the visitor has arrived directly at your website, while a query string in the URL suggests that the visitor may have come through an advertisement.
Use-case
You can use extra filters like GET parameters to find out if the experience of people who come to your website through a query string, which may indicate paid traffic, is different from the experience of people who go straight to the website.
Example
The screenshot indicates that visitors who arrive at the website through a query string have a worse experience. This suggests that there may be underlying issues that can be addressed to improve their experience.