You don't have to type anything on touch screen to use folders. Just navigate.
Of course, hardware buttons (for page up/page down functionality) would be great for that purpose. But at Kobo they forgot that it is an e-ink device, not really suitable for scrolling/dragging. So at least buttons on the screen are needed.
As to Sony incorporating a file browser - yes, they already did!
Good people helped them out against their will
