Not this, the customers cannot simply buy rubles. They must instead obtain rubles by selling to Russia something Russia wants. Not easy, and goes against their own sanctions.
Alternatively, they may be able to buy or borrow some amount of rubles from an intermediary (think China)... may alleviate their immediate problems. Not a long-term solution.
Alternatively, they can go into permanent depression. ----
I'm actually shocked -- Putin waited so long for this obvious move!
Possibly Putin was honoring existing futures contracts, and even extending (on new contracts) historically lower pricing to Eastern European Nations on good terms or neutral to Russia.
Nations signing on to Biden's GloboHomo "Sanctions" would violate payment terms of those contracts.