Given Twitter's fickleness toward developers in the past I'm especially wary.
Getting your company ingrained into a larger part of the app market has huge benefits. Now if people aren't using the Twitter app, Twitter can track them and get data from them if they use an app that relies on Fabric.
The benefit is purely integrating themselves with larger and more diverse user bases.
In which case, I'd be kinda skeptical. If the other tools are mainly loss-leaders for advertising, then Twitter will be prone to limiting or canceling them when the internal politics change.
Which is exactly what they did with API access previously: they cost money to operate and weren't for the moment seen as directly beneficial, so what was previously going to be free forever was suddenly cut back.