Engadget's guide explains that iPhone Handoff lets a single mobile number work across two iPhones. The article says that anyone who regularly swaps between two handsets, whether for work or casual use, should set up the feature.
The piece also covers which carriers support Handoff, though the excerpt does not list them. Because the article is the sole source, there is no independent confirmation of the carrier details. Readers interested in using Handoff would need to consult the full guide to see if their provider is included.
The feature appears aimed at reducing the hassle of managing two phones with separate numbers. But the practical usefulness depends on carrier participation, which the article addresses.