Based upon my experience, the best part about a watch like the Apple Watch is that you don't have to pull out your phone for all of those texts that require no response like "Thanks", "Ok", etc. or for any texts that don't require an immediate response like, "Sounds good, just text me when you get over there". It's so convenient to feel the slight vibration on your wrist, look down, and see that text message on the screen without having to pull out your phone, swipe to unlock it, go your texts, etc.
But...... for everything else, it sucks because you STILL have to pull out your phone to type a response back. Yeah, the watch might have speech recognition on it, but we all know how unreliable that is. And if the message is more than a short sentence, you can't even read the whole message on the watch, so again, you end up pulling out your phone no matter what.
Agreed COMPLETELY re your first paragraph! Second paragraph points out why I doubt I'd own one. But damn, that would be cool for keeping my phone in pocket with short texts you mentioned above. If we were truck drivers, we'd probably do well with that watch, lol.