Although, Bitcoin users that want privacy can maintain being private while holding and using Bitcoin for payment, but the blockchain (Bitcoin public ledger) is available to the public, all Bitcoin transactions can be traced or tracked on the blockchain by any blockchain observer like you or I.


Bitcoin Privacy Model ¹
https://bitcointalk.org/index.php?topic=5229148.0#post_point14

If you can check the recent exchange that was hacked , you will see the addresses the hackers makes use of, the addresses are known and any transaction that occur using the addresses will be tracked. Some cryptocurrencies like Monero that do not have transparent blockchain can be used but just as Igehhh commented, many of these people are illetrates, most of them do not exactly know what cryptocurrencies are. If they have been using naira since and it is perfectly working good for them and getting the job done, they will still prefer to make use of naira. One of the anonymous transaction that can be made is fiat transaction in cash, the reason why the bandits may prefer to make use of it.

This can mislead people, the president of Nigeria do not ban cryptocurrencies, he may have influence about the ban as we know how CBN governor will have to follow his order, or telling the CBN governor that he should do something after the EndSARs protest as a result of Bitcoin used for the funding after the bank account used in the funding were blocked. I am not implying that you are wrong but neither am I implying that you are right as this is politics, but nomally, CBN governor is the one that ban cryptocurrencies in Nigeria, not the president.