Working with channels is a more advanced method of Photoshopping. One that I'm not a huge fan of. I dont personally like that many steps. I dont have the patience for it. But I have heard of it and tried it. I try to keep things simple.
I did this tut as a quick informative tut on the tool. I'm not saying that its the best method. Just another way to go about it. Its another tool in photoshop. Its a matter of preference.
As for quick, quick-er, than selecting with a selection tool such as the magnet, or polygonal tool.