No, it won't. That's a niche market. Features like that mean nothing to the majority of Apple's customers. Think of the "Your Verse" ads; people can do a lot of cool stuff with the iPad too, but you're not going to see most people writing orchestras on their iPads.
Will the iWatch be successful?
Absolutely. There's very little Apple could sell that would not be successful. But it won't make the big splash that everybody is expecting. It will end up a hobby like the Apple TV was when it first came to market.
If you truly believe this is going to be the next big thing, I have some bridges I'd like to sell to you.
I expected somebody would comment that

It's true, Apple has worked their magic in a lot of markets. But cell phones and MP3 players both have had mass appeal. Apple reached into a market that was ready to be blown open by a breakthrough product, and Apple delivered it. Health tracking does not have that same mass appeal. And while the iWatch is sure to be the most successful in the category, it's going to have a hard time establishing itself outside of its niche as a truly useful and successful product. If it doesn't offer anything substantial outside of the fitness market (other than being a glorified phone accessory) then it will have some trouble after the buzz wears off.
That must be why
Nike discontinued the Fuelband, right?