Generally you have to call your friend to know something or to tell him something and it takes lot of of balance of your mobile but whatsapp make it easier for us you don’t have to call or send too much messages by losing so much message pack you just enable data and chat with your friends .I don’t like to make calls again and again I just use whatsapp to ask or tell anything to my friends we can also send photos or videos without any problem or time consuming process .you just send it your friend will receive it I do not believe any other app I just use whatsapp I advice all my friends to use this and all are very happy to take this advice