Note that Hong Kong's Center for Health Protection (CHP) has consistently been way ahead of any other public health establishment in tracking and responding to COVID; they launched on-arrival rapid testing in March 2020 (!) and realized COVID was airborne, not fomite-transmitted, months before the CDC did. They've also consistently released provably accurate numbers. Hong Kong has had a bad response to COVID recently, but all of it is due to the bureaucrats in charge ignoring the CHP's scientifically-based health advice in favour of mandates handed down from the mainland government.
In any case, the numbers show that while Sinovac isn't as great as Pfizer, it's much better than being unvaccinated. The case fatality rate among 80+ year olds who got covid is 15.68% for unvaccinated people, 3.98% for those with 2 doses of Sinovac and 1.73% for those with 2 doses of Pfizer. For 70-79 year olds it's 5.28%, 0.6% and 0.33% respectively. Note that all of Hong Kong's recent wave was from Omicron.
We forget how lucky as a civilization we were to develop mRNA vaccines in response to COVID, and how much better than expectations they were. We would have been thrilled with the efficacy of Sinovac. So while Sinovac is definitely worse than Pfizer, it's misleading and alarmist to say that it's 'basically worthless.'