No, I don’t think it is about “honoring” — he is on a firm legal ground, international law is already dead.
As a guess (and I’m not an economist!): he was waiting for the excess amounts of dollars and euros in Russia to be removed from the circulation... measures for this were taken immediately. The effect was stabilization of ruble (which is traded only inside Russia!) — now it is 95 to USD, up from 150.
https://www.xe.com/currencycharts/?from=USD&to=RUB
watch this chart.
BTW, the Austrians (OMV) announced that does not matter what Putin says they are going to continue paying in euros... we’ll see...
This is a short term stunt that will blow up in their faces longer term. They just cut themselves off from a large amount of US dollars and Euros. The yuan is pegged to the dollar. Others countries want dollars and euros, not their 3rd world bleephole currency.