Implicit in your comment is the idea that no one should ever have any legitimate reason to use a mobile device before going to bed. While I have no doubt many users have to check Facebook one more time or some other compulsive behavior that you imagine, there are users who need to set an alarm for the morning, check what they have to do tomorrow, or even check up on some mission-critical status for work.

Some adults use their phones before going to sleep in order to be non-infantile and responsible.

Super hard, and you know it. Plenty people's willpower is basically depleted by night time.

My own little lifehack here is that my phone stays downstairs, in the charger, when I go to bed. I use an old phone without wifi or SIM to act as a simple, programmable, non-annoying alarm clock. It means that by the time I'm down, I don't need to resist to urge to just check HN one more time.

You did not read the article... It's not about putting down the phone, it's about the light it emits.

Maybe he did. The blue tones are no problem if you simply don't look at the damn thing all evening.

Or if you install software to control color temperature.

I sometimes like to read a book before going to sleep: it's always been a nice, calming activity for me. I also sometimes read books on my phone, and I think that's probably going to become more common (for me and in general) over time. Which of those is the "infantile, irresponsible" part?

As other said it is not necessarily about the using the phone it's about the light emitted from screens of all our devices. T he issue also applies to using other screens at night. Like watching TV right until you go to bed, or even in bed. I guess using your phone in bed to set an alarm and whatnot is a more common case and thus is used as the example.

Do people not put their phones face-down in the night table?

I used to, but as of iOS 9, "hey Siri" no longer works when an iPhone is face down so now it stays face up at night.

Oh, sure. But how about infantile and/or irresponsible ones? I heard there are a lot of us here... ;)

It's not a matter of putting the phone down "before" sleep. That's easy. It's a matter of putting away all screens a full two hours before you want to sleep. That is an enormous pain, no matter how easy it is. And it's so easy to fix.