Quite interesting, dual or single line slots has at times been a key spec on phones especially on Kenyan market but have you ever wondered why the dual ones have a link to China ???
Also read: where to get featured phones in kenya
Well, the question was answered on quora and got an increasing 133 upvotes and more than 100k views.
Most Chinese people, use twin SIM phones because they have an old number from where they grew up, and through which all the local connections are kept, and another number from the big cities, like Beijing or Shanghai or Shenzhen, where they had later on in life moved onto, for better work or studies.
Other reasons include separation of work and private life, etc.
In a country like kenya; one line would be for making calls & messages as the other one for mobile money transfer ha aha!