1) Ability to quickly see changes in the simulator as you're modifying code (one of the main reasons I went with RN over ObjC/Swift, is I can just Cmd+R and boom, my changes are live in a second).
2) Pushing new updates remotely, without having to resubmit your app. Would Go being statically compiled, mean we can't ship bits of executable code for minor updates / bug fixes as we see fit?
3) Debugging is really nice on RN, because you get to leverage awesome JS debugging environments like Chrome DevTools. While I've not yet had a need for a fancy debugger with Go, I could see that as a big sticking point for teams trying to choose.
Nonetheless, really applaud this effort so far, and look forward to seeing more. Go's concept of goroutines seems much better suited to UI event handling, then stringing together a ton of promises and callbacks. And don't even get me started on the async keyword...