The explosions benefit Russia because it gives them cover for a permanent stop to supplying Germany with gas, something that was already a given because Germany would never buy gas from Russia again due to their atrocities in the war. In the Russians' mind it gives them the "moral high ground" rather than humiliation and makes out the West to be the villain. This is typical Russian logic.
On the other side there is no rational reason for the West to destroy the pipelines, outside of strained conspiracy theories that the US wanted to stop Germany from buying gas from Russia and buy it from the US, which was already happening. Nevermind that the risk/reward of such an action would be stupid for the US and that it has other, much safer ways to achieve the same result.