I can assure you that the ban won't last.
Crypto enthusiasts in Burundi will find a way around it... Now that we have tor browser and other VPN-hiding sites out there.
It might last but that won't stop those traders or crypto users to access the internet and still follow and use bitcoin/crypto for every transaction they made on the internet in that country.
This decision comes after some people in the country lost money while trading the various cryptocurrencies. There is no word on which currencies they were, or if the people invested in fraudulent offerings. Even so, the public demand for governmental intervention, and their decision is to get rid of all trading indefinitely. Not a popular decision, but it was somewhat to be expected.
Instead of banning, the government should let its people know the risk of using crypto, guide them on how to protect their crypto-asset or the safety/savings like what they do here in my country.