I was born in Nigeria and grew up there until I was 17 and from what I know about everyday life in Nigeria, the implementation of this system could be astoundingly complex. In the foreseeable future, I think that only about 20% of the population will end up using this system because for most of Nigeria, life is primarily focused around a cash economy.
Nigerian life is rife with many daily issues that foster a large distrust of institutions and the government. Master Card and their POS machines, cash and voting machines would have to build that trust. Life in Nigeria also involves a lot of wary informal trading between many half-educated people (elementary school) who do not use banks, do not use any services that are provided by the government/any large institution, and do not use any automated services at all.
That trust is already lost with Mastercard's association with the Nigerian government because the relationship between the people and the government is quite sour. The government, the leadership of the country (and a good chunk of the people) are daily involved in corruption.
There are many things in Nigeria that you just can't actually do except you bribe, or know someone on the inside who will protect you from having to spend money to bribe. Nepotism tends to be the only alternative to bribery. This sort of thing is widespread, from purchasing a car, to passing an exam (yes, sometimes) to just using a roadside mechanic, to driving from point A to point B (you will have to bribe the police to pass a check point, even if you have no fault). Adopting a checks-and-balances master card system in this kind of a society will be ridiculous at best. The everyday institutions, and millions of people (yes millions!) who thrive on these corrupt systems simply do not want such a system. Neither does the government. The government is the most corrupt of all organizations in Nigeria.
Because the problems are so entrenched, it would take a long time for a large portion of the population to start using this. (BTW The voting part of it is a joke, or maybe a dream).
Master card is probably only seeking to gain with the growing upper middle class that work in a mostly formal economy and mostly live in Lagos. If this section of society adopts their system, they can seek to gain with time. However, they would need to maintain a good wall between themselves and the federal government if they want to gain trust and make not reduce this thing to a joke.