This is a quality-of-life feature that works with the Visual Timer. When enabled, the extension will save the on-screen position of the countdown timer for each specific website.
After you enable the Visual Timer and drag it to your preferred location on a page (e.g., the top-right corner of example.com), this setting ensures that the next time you visit example.com and start a timer, the countdown will automatically appear in that same top-right corner.
This saves you the hassle of repositioning the timer every time you start a refresh. The extension remembers the position per domain, so you can have different preferred locations for different sites.