Don't understand why you would ever need/want to do a bankruptcy as a major. Even on VH Russia should never run out of money.
Bankruptcies help you add quality weight by manufactory spam, which is a kind of indirect governing capacity when you think about it. They're simply stronger than courthouses or blowing up past the GC limit too soon. The other alternatives to blowing up too fast are of course innovativeness and colonial regions.
Level 5 advisors, forts, artillery, cavalry, colonies, great projects, gifts for coalition control, etc all cost lots of money. Russia needs money more than most because it has such good manpower.
Worth noting that you can state something but not full core (saving 50% core cost) it in order to get 50% autonomy and the ability to bank prosperity/use edict while still keeping the normal 25% territory GC cost.
This is handy for smaller nations, but Russia has the governing capacity to comfortably fit all of Eastern Europe even if it requires courthouses and state houses and great projects. Everything else can be a trade company and should be, once the bankruptcy era is over.