And in the day time, if transparent and applied to solar panels, the "efficiency" gain (~10W psqm) itself will dwarf other considerations.( Remembering that bulk of radiative cooling shouldn't happen below ~1300nm) And then there's beating the efficacy of carbon capture at mitigating warming by orders of magnitudes

Nothing to sneeze at. Just be careful of midbrow high-effort dismissals from the old and wise:)

These guys are applying them to solar panels:

https://www.i2cool.com/tideflow/uwJVdixI.html

  "Case Study 2: Solar Farm in Dubai
  Problem: Solar panels lost 15–20% efficiency at 55°C+ temperatures.
  Solution: Coated panels with i2Cool’s film.
  Results:
  Panel surface temperature: ▼25.7°C (from 58°C to 32.3°C)
  Power output: ▲8% (equivalent to adding 2,400 new panels to a 30MW farm)"