Answer:
The Nigerian Stock Exchange or NSE benefits the Nigerian Economy the same way the London Stock Exchange adds value to the British Economy. Investors in Banking stocks in particular have seen spectacular returns recently.
The NSE is an institution which helps businesses raise funds for growth or expansion within their domestic, regional or international markets. A strong NSE means Nigerian companies have access to capital they'll need to become regional power houses or true multinationals.
In addition, Nigerian companies pay tax on their worldwide income. So the richer these companies get, the more revenue in tax is available to the Government to spend on schools, roads or other public services. At least in theory( ahem!).