I personally leave the default option to 'Pin to' because I can hold down Shift while dragging to do an Open With. You could also drag a file over to a running app's icon, wait for the window to get focused, or Alt-Tab to it, and then drop it inside the window.

In the classic taskbar, you could drag a file to an icon inside Quick Launch to open it. You can change this so dragging a file opens it with the program you dragged it to. By default, when you drag a file from Explorer or the Desktop to an icon on the taskbar, it gets pinned to the icon's jumplist. The next option deals with what dropping something over to the taskbar button does.The classic taskbar had no use for middle click so you can set this one to anything you want. The next option lets you configure what middle click does.Finally, you can use the keyboard combination hotkeys, Win+Alt+Number # to access an app's jumplist. You can drag any taskbar button towards the center of the screen to show the jumplist. You can Shift+right click with the mouse to show the jumplist. You can still access jumplists in 3 different ways even if you set regular right click to show the context menu. I recommend you set it to Standard window menu instead of the default Jump List. The 'right click' option lets you change what right clicking on the Taskbar buttons does.Let's explore some of the basic options one by one. Click the icon to access its regular options and right click it to access more Advanced Options. Once you open it, it shows its tray (notification area) icon.

Classic shell taskbar textures