It's not just scrollbars. It's the elimination of window borders. Aside from not being able to differentiate one window from another similarly colored window in the background, it's nearly impossible to click and hold on anything along the edge to resize the window. It's the overloading of the title bar with so much shit like search boxes and extraneous buttons that a user has almost no place to grip to move the wind…
On Linux (e.g. KDE), you can simply Ctrl + mouse drag the window, and then click anywhere you want. This makes it even much simpler than the need of clicking on the border, even with larger borders. You actually don't need any window border at all then, or it can be full of other utilities. There is also some software for Windows to do the same.
Even if that was a great solution for everybody, you still need a window border. Or at least I do. I need that visual separation from all of the other windows on my desktop, and I need it to be thicker than one or two damned pixels.