Progress indication among others. But this is actually the only one retained by current simplified, slimmed and autohiding scrollbars. Here are others: -Disco

Progress indication among others. But this is actually the only one retained by current simplified, slimmed and autohiding scrollbars. Here are others: -Discoverability: Is there more content? (Scrollbar enabled/disabled) How much? (Size of scrollbar) -Jumping to a location in the content -Skimming by hyperfast scrolling -Coasting by holding a scroll button pressed (this one is forever lost because the buttons have been abolished -Providing a space for bookmark indicators/in-page search result indicators There are probably other use cases too.