While they can't use most centralized exchange, their option isn't that limited. They still can rely on decentralized website and P2P/OTC medium such as Bisq and HodlHodl to find Bitcoin seller though.
From what I've understood from
here (Romanian,
here's a Google translation), if it's out of SWIFT, the customers of the bank can only withdraw money, nothing else. So I expect that - in a way or another - only face to face trades could take place there.
I get your point and it's valid point when a Russian trading with foreigner. But i meant Russian trying to find Russian BTC seller where both of them use Russia bank (local bank transfer).