Maybe functionality is in the eyes of the beholder... but Pebble can most definitely do all of those things with the proper app: view calendars/agendas, send canned SMS responses, and view upcoming weather. You don't have to "ask" your device to do it, just press the right buttons. Despite the "coolness" factor, I find it preferable and more discreet to press buttons, rather than using a microphone or swiping a touchscreen. Depending on the app, you can literally cycle through the three things you've mentioned in three button clicks. [1] Also, if Pebble has a killer feature, it's that its battery life crushes anything else I've seen thus far, regularly lasting through 5 to 7 days of 24/7 wear and bluetooth connectivity...I don't think any Android Wear device can do that yet, but I would be really interested in looking at them if they could.
EDIT: FWIW, I don't use Google Now on my phone itself, so I admit that some of the novelty or utility of what it can do from your Android Wear device might be lost on me.
[1] http://www.finebyte.co.uk/?page_id=9
EDIT: FWIW, I don't use Google Now on my phone itself, so I admit that some of the novelty or utility of what it can do from your Android Wear device might be lost on me.