It looks like the pipeline runs through Ukraine. That raises the question ...
Why didn't Ukraine simply shut off the pipeline within its own territory? That surely would have been a lot easier.
This looks like a carefully considered chess move. If Zelenskyy simply had shut off the pipeline somewhere within Ukraine, then there might have been international calls for them to turn it back on. And Russia could have used this as a premise to justify more attacks deep inside Ukraine.
But by attacking 800 miles inside Russia, what is done is done. Ukraine cannot turn it back on. And this is a powerful show of force for the Russian people. It signals that their economic circumstances are going to get worse and worse.
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I did a little more research. It gets better. The loss of sales to Hungary and Slovakia is about $15 million per day (over $5 Bn a year). That's about 2% of Russia's GDP. It's not nuthin', but not decisive.
Here's the interesting twist. The Kaleikino pumping station is vital for blending, meaning its disruption affects the transport of Russian oil to domestic refineries and maybe to other customers like Kazakhstan and Uzbekistan and elsewhere. It might even affect the operation of the Caspian Pipeline Consortium. So this seems rather strategic.