They believed that this decision made was as a result of being the use of cryptocurrency as a means to engage into illegal financial activities such as scam and other fraudulent attempts by the people, you can read further from the links below and drop your opinion on this ban.
When almost all parts of Subsahara Africa are friendly with bitcoin, those North Africans which are Muslims against it. It got better over time but now Algeria is making things worse for their citizens because of their government self-centeredness. I will say the reason you stated above can be what their government said but the main reason they ban cryptocurrencies is because of their ignorance and their illiteracy part of themselves.