The Nigerian economy currently stands as the thirty-first largest in the world, according to gross national product. The country boasts good legal, financial, command entertainment sectors, as well as decent agriculture and oil exports. It has the second largest manufacturing sector in all of Africa, and only South Africa and Egypt have larger economies, respectively.
In spite of its relatively large standing in the world economy, Nigeria has a pitifully low ranking in terms of services - sitting at number 63 for services output. In terms of banking, 29% of people living in urban areas didn't have a bank account as recently as 2007, and due to the high cost of doing business in Nigeria, a lot of banks get involved in practices which aren't exactly within the law - even more so during times of military control. The banking sector is on the up, however, as new banks emerge and grow - it's a far cry from the banking issues the country experienced in the 1990s.
Banking, then, does not play a particularly large part in the country's economy, but it could be said it is essential to the success of any other part of Nigeria's output. The sector continues to grow, and more evidence will likely be recorded in the coming years regarding its success in terms of the population's adoption of bank accounts, whilst the current political stresses on the continent could lead to sudden and violent reforms that could see the economy and the currency either crippled or made in a very short space of time.