The most limiting thing about Exponent is that you can't add in your own native modules. We give you most of the most commonly desired things, but if you need something very custom--like on-the-fly video processing or low level control over the Bluetooth radio to do a firmware update--then Exponent won't work for you and you should just use regular React Native."
Well probably not a small task to support custom modules, and it allows them to get a pretty powerful tool with a nice core set of features out the door relatively quickly. If exponent becomes successful I imagine they'll add support for custom modules.
