In summary:

Remit $100 to Nigeria and there are the amounts in Nigerian Naira the recipient receives:

Bank Wire NGN 32,000
Western Union : NGN 33,750
PayPal: Cannot received fund via PayPal in Nigeria
Bitcoins: sell at LocalBitcoins.com Nigeria: NGN 47,100
Cash USD: NGN 49,500

Cash Dollars convert to the greatest amount of local Nigerian currency but there remains a problem: How does the expatriate Nigerian deliver physical cash dollars to his family in Nigeria?

Using Bitcoin is a close number 2 in terms of the total return, but does not encounter the problem of physically transporting currency to the destination.