anyone who thinks home kit is a better thing for apple than health kit has many screws loose. first, i care more about monitoring my health, even if it's just how much activity during the day, my heart rate and blood pressure. but from what rumors i've read thus far it will do more. so do i want that to spend my money on or would i rather be able to turn out my lights and lock my doors remotely or while i'm sitting on my sofa?? for me it is a pretty easy choice.
cost wise it is too. even if the watch is $600 to $1000 dollars, which t won't be. it's still the cheaper thing too. $50 bucks for a wifi light switch. because it would be tough to retrofit a house any other way. if i add up my switches that would putty over $1000 very fast!! plus installation. a cheap electrician will charge you $10 bucks a switch. 4 exterior doors at $200 per lock. that's bluetooth so you may need something more to use it remotely, but thats another $800, a garage door opener that can be used with home wifi is another $350+.
When force-ranking the two, I'm also more interested in health benefits than James Bond home automation. I'm also a 40 year old male (aka: not Apple's bread and butter target audience). The VAST majority of society (and Apple's true target audience, under 40) cares more about how cool it is to turn their porch light on from Starbucks. While I have the capacity to also find that cool, I happen to find monitoring (say) my caloric intake, cooler. Again, I'm 40. My "cool" priority list is evolving.
That said, I think iWatch will prove so much bigger than most anyone is considering/discussing. Should be fun.