It's not window dressing, it address the symptoms, not the cause. But it's the symptoms that are causing the problem for us, it's enough to address them. We need to buy time to solve the root cause.
Blocking sunlight takes off pressure to stop driving up CO2.
Rising CO2 is acidifying the oceans, something shade helps not at all. Resulting ocean ecosystem collapse eliminates access to protein for a large fraction of humanity. Mass famine provokes global war. War halts sun blocking activity. Temperature shoots up faster than ever.
Furthermore: rising CO2 is already interfering with cognition. Shade helps with that not at all.
Money is fungible. Money spent on shade is money not spent on addressing the cause of multiple identified problems that shade does not help.
How much more heat forcing do you suppose would be driven by burning enough rocket fuel to put millions of tons of crap into orbit?
The whole prospect is BS, but it exerts a sick fascination that is harmful by itself, as it makes it seem like disaster can be averted any time with no fundamental change.
Makes no difference. The point is that devoting enough resources to blocking insolation diverts those resources from measures that address the root problem.
But disaster comes on just as fast, however much you make it look like it is not.
Blocking sunlight, by whatever means, is a disastrously bad idea.