Here’s the thing.
Xcode 6 is beta software. Coming in very new, you probably don’t want to dive in trying to learn with a moving target.
Maybe it’ll leave beta tomorrow with all of Apple’s other announcements; I don’t know.
But if you want to learn today, then either stick with the stable Xcode 5, or use the linked template with Xcode 6 to keep moving forward.
Yes, the preferred technique could change very soon, but it’s what works right now.
Apple has demonstrated repeatedly that they’re not afraid of changing things, either in software or in hardware. No matter what you learn today, it will change; the only question is when. But it doesn’t mean that what you’ve learned previously is useless; it’s a good foundation for what’s to come. See, for example, Aaron’s blog post regarding Swift.