Most politicians in Nigeria have bank accounts abroad so why shouldn't you. The value of the naira is decreasing. As of now it is 366 naira to 1 dollar.
There are several reasons why you should open an offshore account
1)War:
There are several mini wars going on in Nigeria, Herdsmen, Boko Haram in the North East, Niger Delta militants. It only takes one small thing to happen before a full war takes place in Nigeria. When there is a war the value of the currency drops
2)Corrupt Government:
The Senate just approved a loan of $22.7 billion dollars from China and it is rumored that 40% of the money will be used to pay consultants who helped secure the loan. Just Imagine. The government also wants to borrow money from pension funds to fund projects. They will probably do it and won't pay back.
If you think you're safe by buying dollars and keeping it in a dollar account in a Nigerian bank you're not. The government can take it too.
3)Protect your Assets:
As long as you have money in a Nigerian bank whether Naira or Foreign currency the government controls it. They can seize it if they like. What will you do?
It is not Illegal to own a foreign bank account as long as you pay your taxes.

Some foreign banks require you to open a bank account with a minimum balance $6000, $80,000,$1000. It depends on the bank and the country they are in.
If you don't have that type of money you can buy Bitcoin or open a TransferWise Border less account. Bitcoin is risky. The value can go up or go down. Bitcoin might become valuable in the future or it might not exist. No one knows

TransferWise is a company that helps make international money transfer easier but in 2017 they decided increase their services by also offering Border less accounts. It is similar to an Offshore Traditional bank but with less fees, You don't need to have up to $50 to open an account. You can receive and send money in different currencies making it easier for you to do business with people abroad.
If you want to register for the TransferWise Border less Account Click the link below. You can send up to £500 without any fees If you click the link the link below:
https://transferwise.com/invite/u/ugochukwue36