Honestly, I think it depends on a lot of factors.
For the record, I own two smartwatches; the original Pebble and a Moto 360. The Pebble has mostly been relegated to a drawer because I just don't use it any more... probably go on eBay pretty soon. My Moto 360 gets used daily because it's really handy for my work. I work in the tech field; I'm a consultant for a large company who travels all over two states talking to customers about their technology needs.
For my part, my Moto 360 nearly always gets questions at the table. "Do you like it?" "Is it useful?" etc. and I'll tell you exactly what I've told them; it depends a lot on your use cases.
I use my 360 all the time. It's right there on my wrist, so even while driving if I receive a notification that I've received a text message I can flip my wrist over and check the summary on my wrist to see if I need to respond to it, or if it can wait until I get to my destination. I don't need to pull my phone out of my pocket or retrieve it from my jacket that may be hanging in the back of my car (depending on where I put it). I get reminders of appointments and again I don't have to rely on my phone to do the same. In fact, because the alarm on my 360 is vibrate only I can actually turn the notifications completely off on my phone most of the time and I still know what's going on. Similarly, in a meeting when my phone rings I can immediately see who's calling at a glance and throw it off to voicemail. I also like the ability to use the microphone in my 360 to set timers, set an alarm, bring up the weather etc. For my use case, it works extremely well.
There are some things I wish my 360 did though that would be cool. I wish airlines in particular would get with the program and allow me to bring up my boarding pass QR on the screen of my watch rather than digging for my phone. American Airlines already has an app for the Android Wear OS, but it doesn't do that... annoying. But as a general rule these are niggles that will be ironed out as/if people buy more of these devices as you said.
I'll also note that because I'm not turning my phone on every time there's a notification or I want to know the time, my battery life on my phone actually increased when I moved to a smartwatch.
As far as charging every night, that's less of a problem than you might think. I don't wear my watch to bed, so I have my Moto 360 charging base sitting on my nightstand right next to the cable for my phone. Instead of setting my watch on the nightstand itself, I set it on the charging base and voila... no problems. It's no more a chore than setting it down, really. Yes, it can be frustrating if you are traveling and forget the base, but that's also true of forgetting charging cables for any of your other devices. So far it hasn't been a problem. Battery life also isn't half bad on the 360; I can get about 30 hours of tested time out of mine... given that I charge it nightly that's pretty bloody impressive and I have no complaints about it.
I do agree though that this is still a nascent industry... people haven't really found that killer app for a smartwatch yet, but for people like me who are natural early adopters, techies and people who just like stuff like this I think there's still a market.