These sorts of laws are a signal of a very weak and controlling government, which often indicates that the politicians themselves are screwing over their citizens at every opportunity with complete hypocrisy. Overseas banks don't like to hand over information to the Nigerian government necessarily, because it can be so petty and this is a prime example. Crypto has the opportunity to draw more money into the local economy, if it was just left alone, but instead the banking and currency exchange vultures throw their scraps to the politicians who in turn ban the competition against them. I imagine that lots of extra cash would flow in and be beneficial to the wider economy if this law was scrapped.