Nice to know. I've had that on before, but because the "picture" shows moving a window, I hadn't known that it worked for all dragging options, including those with modifiers (like copying a file). I just tested, and it does. But I find the "left pinky" on Caps Lock to be more convenient than repositioning my right hand to do a 3-finger drag. And I use it for other clicks besides drags --- that was just one case I liked.
What I'd really like for 3-finger drag is the ability to move windows without having to click in the title-bar. That is, 3-finger drag anywhere within the window to reposition. Do you know if there is any way to enable this? Currently I use Better Touch Tool (another excellent configuration program) for Cmd-Option-Click-drag to reposition, but this sometimes interferes with certain applications.
Why not 3 finger drag (they moved it to Accessibility in El Capitan)?