In large part it has to do with the level of tech available. Bandwidth in many parts of Africa is very slow, so SMS is preferred as a workable solution for dat

In large part it has to do with the level of tech available. Bandwidth in many parts of Africa is very slow, so SMS is preferred as a workable solution for data. M-pesa uses SMS on any low cost feature phone, while Square requires a more expensive smartphone with apps and data plans. People use what is practical in their context.