I like the idea in theory but I always use my phone to actually fall asleep by listening to some monotonous audio. Before doing this I had extremely hard time falling asleep.
For me before I made the change the last thing I'd do at night was look at my phone, the first thing I'd do in the morning was look at my phone, and if I woke in the night I'd look at my phone. Bed is now a mentally distinct place for me, which helps my sleep a lot.