Batteries aren’t just about using the generated energy in a useful way, they are about making renewables more profitable by giving them a buyer for all the energy they can produce. Miners are money batteries in this way - they can be fired up on demand to soak up energy the grid doesn’t need, and instead of finding a buyer they can just directly convert excess energy into income.
Miners suck money away from real batteries who would otherwise be smoothing out the peaks. It's not good for efficiency or climate change.
People point to miners using up excessive hydro or geothermal capacity (Quebec and Iceland), but these areas were prior doing low-carbon factory work such as aluminum manufacturing.
