OK, I just figured out something: I had been wondering all along what exactly was the use of the Bluetooth radio in the T-Slim X2. But, in the pipeline page, this is what Tandem says:
the t:slim X2 Insulin Pump […] builds on the original with a variety of improvements including an advanced Bluetooth radio for communication with future technologies.
You have to think that the X2 will be able to communicate with a cellphone. This opens many options similar to the Dana RS.