For us more than them.
Medium term and beyond?
We will pull ourselves out and replace the loss, but it will NOT (ever again) be cheap.
They can't eat oil.
They won't have to starve if anyone breaks the boycott.
And wars are expensive.
The way we fight them, Ruskies collect as they go, so it takes longer to cost them.
We could always count on help from the UN.
But Russia has big trouble. The have short term leverage (oil and cash) but a long term problem. They're dying. The men have a high degree of alcoholism and the women are voting with their bodies and not having children. They are half the size of the U.S. in population and shedding half a million people a year. The demographic situation is so bad that in a generation they will have only a few million women of child bearing age. Also, in 40 years or so their population will be 1/2 Muslim.
Can they use their oil and cash now to solve their long term problem by gobbling new territory? I don't know. I tend to doubt it. Mergers are tough and those by force more so. Forced socialization of disparate populations takes hundreds of years if it works at all. The last time they tried it came unraveled in only 70 years. It will be much tougher this time around. This time they don't have time on their side.