Yes.
In Moscow we could use Dollars more or less at most places, but deeper into the country it was harder for the Russians to use dollars so the local economy was Ruble only.
If the Ruble continued to fall, and someday the exchange markets reopened, they could buy more Rubles with the dollars they exchanged with us. This is important because while the exchange rate continued to worsen, their income stayed relatively the same. If they made (pulling a number out of thin air) $10,000 a year, or R15m at the start of our trip, they were only making $2,800 a year at the end even though the number of Rubles they made stayed the same.
If the Ruble continued to fall, say to 8,000:$1 they'd end up making less than $1,900 a year. However, if they bought USD from us at 5500:1 it meant that if it fell, they could buy back 8,000 Rubles for each dollar later, keeping them closer to $2,800 exchangeable dollars.
If the Ruble reverted back to the original rate (1500:$1) then they'd lose their shirts because they just gave us their currency at less than 1/3 value.
Just as importantly, if they were making about $10,000/year, exchanging $400 or whatever with an American kid meant that half their monthly salary was locked up in nonexchangeable USD. The USD had value, but it was non-liquid at that moment.
IIR they weren't able to exchange the dollars until later that year and there were caps on the amount that could be exchanged at once. The next year we repeated the exchange program and I believe some of those dollars we exchanged with them were brought with them to use here.
A few years later, in 1998 the Ruble was reformed on a 1,000:1 basis.
Things were devaluing so fast that people still had Kopek coinage sitting in coin jars that were unspendable and stacks of low denomination currency (1 Ruble to 500 Rubles) that while spendable, were incredibly inconvenient.