The Chinese vaccines do provide substantial protection against the most severe outcomes, though the mRNA vaccines are indeed better. Countries using such vaccines should be trying to provide at least an mRNA booster, especially to people at high risk.

The bigger problem though is that a significant proportion of elderly people remain unvaccinated. Look what happened in Hong Kong to see a prediction of what will happen if Covid gets loose in mainland China without a more substantial vaccine drive.

Chinese vaccines are slightly less effective, but they do work, you can check the numbers in my country, Uruguay.

Pfizer has outperformed Sinovac, but it still provided protection.