Viber solves the issue of connectivity especially calling foreign counterparts at a lower charge. While using the Viber App one can call any foreign number thus reducing your phone charges. It also helps to contact your teams when traveling abroad. The biggest advantage that Viber has is their price for international calls. If you call a local phone in Morocco or Tajikistan or countries where internet connectivity isn't always ideal, the cents per minute spent is ideal. Basically, for 5 dollars you can have a 45min -1hr talk. It only adds up 10 fold if it's a mobile number. Other than that it's a VoIP app, so no need to pay for the rest of Viber calls.