The concept is beautiful, but it goes against the principles of how people interact with a computer.
Scrolling is not an element of the web page, it's an element of the computer. If it's unique to every page, it's jarring and taxing to have to re-learn every website. Some sites use black backgrounds. Textareas use scrollbars too.
The reason scrollbars work is because they look the same consistently for each individual platform. You don't have to learn a new scrollbar for every page (although some break this pattern anyway). When they're the same, it's less mentally to parse for each page load so that the user can focus on what's really important: the content.
Scrolling is not an element of the web page, it's an element of the computer. If it's unique to every page, it's jarring and taxing to have to re-learn every website. Some sites use black backgrounds. Textareas use scrollbars too.
The reason scrollbars work is because they look the same consistently for each individual platform. You don't have to learn a new scrollbar for every page (although some break this pattern anyway). When they're the same, it's less mentally to parse for each page load so that the user can focus on what's really important: the content.