Beyond how small and fiddly using a watch-sized touch sensitive display is, you can use a Pebble WITHOUT needing look at the screen. I often clear notifications or start a stopwatch without looking at the watch.
The more I look at Android Wear and the Apple Watch, the more surprised I am just how right Pebble seem to have got it.
Personally I won't buy any wearable with a display that can't be read in direct sunlight. Since my phone is hard to read outside, complementing it with something that shares the same problems seems a tad silly.