There is one very obvious downside to revealing the transcripts of private, classified, diplomatic telephone conversations as the naïve and artless Americans – on both sides of the conflict which marks the modern United States political class as more interested in scoring points against each other than working out what is best for their country – have done to prosecute the shenanigans over the Trump/Zelensky conversation.
And that downside is that no other country is ever going to trust American politicians ever again with the discussion of delicate material across a telephone line (secure or otherwise).
Although as a result of US antics on the world stage over recent decades, I doubt there is much of a solid trust level towards America remaining in many parts of the world. That Russia has seen need to express this openly in this TASS report, is ample evidence of that. I get the impression the Russians are not amused by the latest US circus act. They will not be alone in that.