That's an interesting paradigm. I do take my Casio Protrek off during sleep, but I kinda enjoy the fact that my watch is the single gadget in my life that requires zero maintenance. It'll outlast my body in any and every circumstance. I basically only need to replace the battery once every 5-7 years, since it just charges through the solar element that's the surface of the watch dial. I feel like having to plug the watch into a charger is yet another thing to worry about during the day. And with my chaotic life, there'll be a few days during the week where I won't know where the charger is, or I left it at work, or it's in the car, or the nearest outlet is occupied by the kitchen blender, and I'll be too lazy to reach the outlet in the next room, etc. I feel like a month would give me reasonable legroom to keep it constantly running.
In my perception, a watch should be something that is zero hassle, and smartwatches just ain't it.
I guess with everything it's a trade off. I get a lot more functionality than a standard watch but the trade off is once a day I need to stick it on the charger for a few minutes.
Unfortunately, the technology just isn't there.