Their vaccine is not very effective against omicron, and they have far less hospital beds per capita than the west. So a 'flatten the curve' strategy will cause a lot more deads than it has in Europe and the USA.
The difference in effort between keeping that kind of curve flat and ZeroCovid is small. I would even assume that ZeroCovid is easier than flattening the curve. While ZeroCovid is not an exit strategy in some areas it works better while waiting for an effective vaccine or some other exit strategy. So presumably that's what they do right now.