They not only add prototyping, but also allow sketch cloud to be a library host:
Prototyping: You can now connect Artboards with Links and Hotspot layers to create prototypes of your designs that can be viewed in Sketch Preview, Sketch Cloud, and Sketch Mirror on iOS.
Libraries on Sketch Cloud: Files uploaded to Sketch Cloud can now be installed as Libraries directly from Cloud.
Can't wait to try out! Not gonna install right now though...
They not only add prototyping, but also allow sketch cloud to be a library host:
Can't wait to try out! Not gonna install right now though...