He is lying. It is easy for a dictatorship to destroy cryptocurrencies. Most people know that the Chinese Communist Party has GFW, but few people know that they have stronger means than GFW, the whitelist mode.
Now let's count how many times he in particular had banned Bitcoin and then in-banned it, the banned again and unbanned again.
Putin knows he's powerless against Bitcoin. Everyone is. No one person can gain privileged access into the system.