Who needs SWIFT? Who could possibly doubt that an alternative Russian controlled interbank financial transaction system would be the apex of reliability and honesty?
SWIFT isn't even a monetary transactional system. It is a messaging system.
If messaging can be arranged through other avenues then international transactions could still take place.
Most people outside the US and Europe do not share your trust in the Western system, where services are getting cut over political considerations. Russia and China are apolitical in trade so far.