Steelman: in the 2000's and 2010's China did not know if wind power and solar were viable in the long term. They put a lot of money in wind & solar, but also lots of alternatives: nuclear, coal, hydro, geothermal.

By 2020 it was obvious that wind & solar were viable long term, so investments in nuclear et al dried up. But they weren't convinced that batteries were viable long term, so they built a lot of coal peakers for night power.

By 2025 it became obvious that batteries were more viable and cheaper than coal peakers, so they've started to build battery storage at a vast scale.

So steelman is that the OP's viewpoint is ~10 years out of date.

They know that sometimes it's not windy, and they know about night.