What Opie does is allow you to make custom rings that you fill with your spells. You key bind this ring so when you hold the key bind your ring pops up. Then all you do is move your mouse in the direction of the spell and let go of the key bind and that said spell will be cast. You should notice that inside the ring is a small circle with an arrow around it. The arrow will be pointing the direction your mouse is and will glow the color of the skill (or if you made a custom ring, it will glow the color you set it to).
What makes this superior to normal keybinding is that you can attach a ton of skills to 1 button. Once you get used to where each aspect is located on your ring, all you have to do is just press you key bind while having your mouse in the right direction to cast your aspect. I personally bind my aspects ring to middle mouse click, so all I do is swing my mouse in the right direction and click middle mouse button for whichever aspect I want.
|Mouse In Center of Screen|
|Mouse Pulled Up Towards Top of Screen|
|All The Different Custom Rings|
|My Misdirection Custom Ring|