Bitcoin P2P transactions cannot be banned. There is no mechanism with which to detect that a Bitcoin transaction has been made, let alone detect who has made a transaction[1], since you can broadcast a transaction with a completely different IP address outside of Belarus' authority.
Maybe he wants to ban exchanges or off-ramps or the equivalent.
[1]: Outside of the very obvious and standard blockchain analysis services, but even these require a trail to already have been made that goes through a KYC service.
You are very correct. I wonder what mechanism they are going to put in place to be able tell if a particular set of bitcoin transactions are from P2P users. Just like what happened in Nigeria, when the apex bank banned cryptocurrency and asked all commercial banks to flag accounts associated with crypto-related activities. Nigerians resorted to P2P trading in order to stay off the radar. In my own opinion, I think this is just a bluff. It's another way to tax it's citizens by forcing them to register and trade on a centralized exchange approved by Belarusian government.