I can think of one more potential downside: light polution is bad enough already. In the author's case, 8x higher lux values. Insect population in Germany has dropped by about 75% since the 70's. A recent The Guardian article names light polution a key factor.

In principle, it's possible to shield your windows with thick curtains, but I know many people won't bother, some will openly boast them, and it may even lead to more of them being hung outside when people see how great they are.