Truth is that most of Nigeria government policies in the past few years have been anti people, don't let anyone deceive you into believing that the ban is strictly on banks not trading on cryptocurrency.
If you are observant you will notice that most exchange platforms have disabled the purchase of cryptocurrencies directly from Nigeria bank accounts, you are only allowed to withdraw because they don't have the right to withhold your money if you want it, while they seek more clarification from government on the new policy.
I work in a bank, and the instructions from CBN to us is not in line with your position. Every bank have started putting together teams both on regional and branch levels to ensure compliance to the policy to avoid sanctions, I happen to be part of the team in my office and our work begins by Monday.
Unless the Nigeria government came to realize how harmful the policy will be on the populace, and decide to double down on it otherwise the part of the circular that said "identify persons and/or entities transacting in or operating cryptocurrency exchanges within your systems and ensure that such accounts are closed immediately" remains effective, and that includes your account if you perform any crypto transaction after the circular was sent out.