I doubt that most centralized hubs will process transactions out of
benevolence - they will take a cut from every transaction. Even if the
Lightning Network works in practice (which is doubtful) and even
if somehow it manages to gain traction in the African countries you still
have the problem of funding LN channels in the first place.

It would not be of much use to people in poorer countries when LN
transactions are dirt cheap (which they probably will not be when
the liquid LN hubs will be run by banks and exchanges), but to get started
you would need to pay a 20 $ fee for the funding transaction on the BTC
main layer.