Yes, I definitely use my iPhone less. I leave my iPhone in its charging stand as I wander around the house during the day, relying on my watch to notify me of pressing issues. When I need a larger screen at home, I use my iPad, so my iPhone only really gets used when I'm out and about and need the larger screen for something. It's a great iPhone accessory.
We were at an auto parts store today and the cashier asked us if we could take calls on our watches, so my spouse activated Siri on his watch to call me and I answered a few seconds later. She was very impressed.
I really like the way Apple produces high quality products that work almost always exactly as you'd expect them to. And when things don't work properly they work diligently to correct the issue, either replacing the hardware on the spot or fixing it no questions asked with your AppleCare. I recently purchased a SmartHome Hub Pro to use Siri to activate my INSTEON switches around the house, and to also access my devices remotely when away from home. The Siri control only works occasionally and the remote access promised using my Apple TV 3 as a gateway hasn't worked at all. So, SmartHome basically released a clear beta product that doesn't come close to working properly. I don't know how much of this is due to bugs in Apple's HomeKit, or in SmartHome's iPhone app/new hub implementation, but the result is mostly useless, and knowing Apple's reticence in releasing faulty hardware that would hurt its brand, I suspect most of this deficiency is due to SmartHome eager to pocket a few extra dollars in the short term vice waiting to release a product that mostly works as promised. I'm currently having a similar problem with the new Withings Home camera, which I hope will be good enough to replace my DropCam Pro down the road, since Google recently acquired them. Unfortunately, today my Withings Home camera's power died, after only six weeks of use. If this were an Apple product, I'd take it to a local Apple Store and get it swapped out in an hour. But, since it's not, I'm playing the email tango to see how they handle the repair/replacement. Most of today's technology companies are only interested in the next quarter's profit/loss statement, and skimp as much as they can when rolling out a new product. Apple stands out as a beacon in the night in comparison. If Apple had produced either of these products I'm sure they would have been more expensive, but I'm also sure they would have mostly worked exactly as promised, and when a quality control issue reared its head, would fix them ASAP.