My partner is Ukrainian and apparently the Crimeans which were recently annexed and now have to switch are utterly shocked by state of e-banking at their new Russian banks; which doesn't bode well for their efforts...
The use of card payment schemes as a mechanism for sanctions in this case demonstrates external political influence. Maybe in this specific case some would agree with that, given Russia's recent track record. But just imagine the response if Russia could do the same to the US or the major economies of Western Europe. Or consider a more ethically dubious example, like the UK invoking terrorism legislation to freeze assets when Iceland was in financial difficulty not so long ago. More than the political influence, these measures demonstrate the rather arbitrary nature of the services these big companies provide, or don't provide, particularly across borders. For any first world national economy in the 21st century to remain vulnerable to some big commercial interest getting upset and taking the ball home, whatever the underlying reason, seems unwise on the part of the corresponding government.
The use of the financial sector as a political weapon is concerning (but that is more possible with state run financial institutions). I'm not sure how you prevent that without basically allowing mega-corporations to be above any national laws.
What we really need is an international court that can arbitrate these kinds of disputes.
Of course, the "security deposit" isn't for security against these companies failing. The deposit will help with the squeeze Russia is feeling, and on the other hand this whole law would allow the Russian one-party government (which doesn't know any kind of division of power, by the way) to extort Visa and MasterCard.
I don't know if building a state-controlled credit card processor is worth it to risk being cut off from Visa and MasterCard. You would certainly expect foreign businesses to be extremely careful or suspicious toward such an entity...