You are assuming that people in the developing world can afford a computer just as easily. The importance of having an information device that connects to the internet cannot be overstated in places where education is not the primary concern. Early access to technology will inspire many more kids to learn programming when they can afford one.
I agree there are some strong upsides, but phones make it difficult to participate in a meaningful way at the higher levels of the information economy. They're consumption-oriented devices. Here in Vietnam I see a lot of people that have blown their entire computing budget on a high-end mobile phone and I worry that they may have stunted the growth of some of their talent as a developer, writer, artist etc.
I realize that developers are rare but the money my grandfather invested in a C64 in 1983 has been repaid many, many times over. I'm not sure I would have the same incentive or opportunity to learn now.
