The philosophy is really interesting. As I understand it, when there are changes to the data they render to a shadow DOM (which is very fast since nothing is actually updated on the screen), diff it against the live document, and then use the diff to update the document. The result is that re-rendering the whole UI becomes so cheap that you can do it whenever something changes rather than using data binding to update values.
It would also be interesting to experiment with server-side rendering for client-side apps.
An Instagram engineer talking about it: http://qr.ae/GtKbP
Sounds like a very fascinating alternative to data binding!