OK I promised I'd be back to report, so here goes...
As planned, I did wear the Asus the entire week, weekend included, then took it off for a few days and went back to the old rotation.
Now back with the Asus for a few days, here are my thoughts:
First, while a smartwatch is far from being a necessity - it's more like halfway between "gimmick" and "nice to have" - it somehow makes sense. Because Android Wear works quite well, it actually makes more sense than 1st generation smartwatches (I should know, I have an "I'm Watch" and I did try it on for a while).
One of the slogans used by Goodle is "the Multiscreen World" - this is the essence, more than being a wearable it's having a second screen. I found it useful to be able to see incoming messages while my main screen (phone) was used for navigation. It was also quite useful, and came natural, to peek at the wrist for quick updates (messages, appointment reminders etc.) while my phone was away. It's funny, because "away" sometimes means two feet away or in the pocket, and yet - turning the wrist makes sense!
I also found it quite useful to be able to feel incoming calls while I was listening to music. When at work, I'd listen to music streaming from my PC (not the smartphone) so incoming calls do not interrupt it. So it's good to know if a call comes in, I'd get notified.
Another Google slogan "information that moves with you" doesn't make all that much sense, since you still can't move away from your phone.
I can also judge this Asus as a wristwatch. In my opinion, the main objectives for a watch are: 1. Esthetic, a non-feminine jewelry if you will... 2. a statement of personal taste (and for some, relating to a brand, though I care less about this) 3. a conversation piece, and lastly, and less importantly 4. to tell the time.
So in that order... 1. This ZenWatch passes quite well as an esthetic piece, it looks good and feels good and there's nothing cheap or tacky about it. 2. it happens to match my personal tastes in enough ways - even the leather strap is good for me - so as not to be a compromise. I chose it over LG and Motorola because of that. 3. It is very much a conversation piece. I was surprised to get asked about it so many times a day, even more than I get asked about my car (and I get asked a lot... Abarth Punto Evo is a rare beast here), and I'm this shallow dude who likes the attention... 4. It even tells the time - though I wish the 'turn wrist to turn on screen' had more immediate response, it takes about half a second to show the time.
Personal conclusions, I'd only call these 'recommendation' if you happen to be like me...
1. Yes, it is likely to become my main timepiece while at work.
2. I believe I will stick to my old mechanical watches when going out, in the evening and weekends.
3. I do see how a watch lover could fit a smartwatch in daily rotaion, unless a 100% fanatic.