It’s a more or less useless card. If they use it (maybe even if they only threaten to use it), they might get what they want in the short term but there’ll be a rush by the countries affected to never be put in the same position again. Some countries having to pay more for a subset of the energy they use may not be as expensive for them as it is for Putin to lose a large percentage of his revenues.
China would be happy to buy the gas, and the pipeline there will be complete by summer.