Disclosure: I haven't worn a watch for over ten years.
A statistic I read recently stated that 54% of people today don't wear a watch. Further, there was a claim that you can sell another watch to someone who already has 20 watches but you will have a really hard time selling a watch to someone who is content without one.
So Apple's watch is undoubtedly a device which will polarise people; marketing 101.
Personally, I don't do jewellry nor fashion. The Apple Watch, more than anything, currently looks to me like an iPhone accessory (yes, the $350 device requires you already own a modern iPhone). Don't get me wrong though - Apple have clearly re-invented the watch, the interface looked well designed and like nothing on offer from the competition.
What might get my interest - an Apple Watch which is your personal profile on your wrist with basic data internet comms and you can wirelessly connect to screens and other peripherals. Now, I'd say that's 5 - 10 years out, if it ever arrives before the Apple Tattoo.
From a purely minimalist viewpoint - it's well known that categories diverge over time (look at the iPhone timeline from 2007 as a good example) and that falling into the brand extension trap can muddy the prospect's perspective. In terms of keeping my life simple and uncluttered, and distancing myself from technology and interruptions the Apple Watch isn't for me. I do think it will appeal to teenage girls who love the illusion of attention that constant interruptions bring. And anyone with similiar psychology.
In short, I don't yet see a "must have" reason for the Apple Watch as announced.
As a former 5" Dell Streak user I have far more to be excited about with the release of the iPhone 6 Plus.