Smart Devices have powerful hardware and operating systems and the generated applications can take advantage of it.
As of GeneXus X Evolution 2, the Smart Devices Api includes capabilities to interoperate with the AddresssBook, Calendar, Messaging Services and others.
(Note:The Smart Devices API is of course not the only one that allows integration to other devices' featues. Take a look at Domains with Special Semantics to see more related features or at the GeneXus X Evolution 2 Samples how seemless the apps integrate and run in the Devices).