The "Back to the Top button" offers the user a quick option to jump back to the top of a long page.
The BTTB is intended to improve usability for the user, make them move around the page faster and give them an active advantage when navigating.
As defautl behaviour, the page inherits the configuration from the parent page. If the button is enabled on the parent page, it will be also enabled here. You can reset this by checking the 'Reset parent configuration' option. In this case, you need to enable or disable the button on this page by checking the 'Enable button here and its children' option. However, if you don't want children of this page to inherit this setting, check: 'Enable button only here'.