Toyola efficient charcoal stoves

In 2003 two Ghanaian entrepreneurs started to sell the energy efficient charcoal cook stove "Toyola Coalpot" to Ghana's urban poor population. These cookstoves are often given with subsidy (including C02 compensation) to Ghana people. After all these years we see limited use of these cookstoves in Ghana. We can doubt if this is the way to go. Does this really help to reduce CO2?