Russia doesn't need to resort to Bitcoin, when they can easily use their own SWIFT alternative or China's. China is conveniently friendly with Russia these days, is rapidly expanding CIPS, and would likely welcome the chance to expand it even more.
The existence of these alternatives is one reason Russia probably won't be banned from SWIFT in the first place.
It'll be interesting to see how it unfolds. Presumably for Russia to use СПФС or CIPS other countries (or banks?) have to use it too, otherwise they can only pay themselves.
Are there any downsides to making a payment through СПФС rather than SWIFT? For example, are you revealing information to the ФСБ, or exposing yourself to counterparty risk from the Russian government, or making it possible for the Russian government to cut you off from your payees if they want to level economic sanctions against you? A potential upside of Bitcoin in this sort of situation is that it's neutral: nobody can cut off your access to it, everybody can see your transactions (but without names and places), and you're only exposed to counterparty risk for the few minutes until your transaction is confirmed.
But, again, I don't think that'll happen in the next couple of years, and possibly never.
The existence of these alternatives is one reason Russia probably won't be banned from SWIFT in the first place.
Archive from The Economist: https://archive.is/CHiiI