I wonder if the higher rates of depression here may have something to do with this (interestingly, I remember reading somewhere that suicides in the Nordics peak in Springtime).
Mind you, most hotels here that expect foreign guests have blackout blinds or at least very heavy curtains,
I have blackout curtains nowadays, and I've also gotten used to the light somewhat, but I still miss proper rolling curtains that completely shut the light out.
[1] https://stuffdutchpeoplelike.com/2010/11/24/no-8-not-owning-...
On the other hand with proper outdoor shutters or roller blinds[0] you can easily get a room pitch-black.
[0] https://www.schenk-sonnenschutztechnik.de/uploads/tx_frsuper...
The title of the video is wrong, by the way. It is not Rouladen, which would be a dish of filled rolled meat, but Rollladen. Rollladen is literally rolling shutter and it is really written with three l in a row.