yes they care because their risk to reward ratio just went to shit, their word is garbage now

so essentially anyone lending them money needs to accept payment in rubles (that alone is a big issue for most lenders, even crooked ones) and anyone lending to them needs to do so knowing they lacked the capital to pay off their previous debts INTEREST (let alone the actual debt), there is also the risk that they default outright and run out of capital to pay back any of their multiple lenders a single red cent

anyone lending to them are going to demand a much higher interest rate which will hurt the borrower (russia).. there is also no way to collect on a debt if they do not operate in good faith or make good on their promise, what is China going to do to collect? invade them?