100%.  I switched to a flip/dumb phone for a few months at the beginning of this year and I felt like a completely different person.   I would actually daydream and come up with ideas again.  It ended up being too obstructive and I unfortunatey switched back. 

Since then though, I've tried a couple easy habits that have really helped.  
1. Keep it put away (out of sight and out of touch).  I'll zip it into a pocket of my backpack when I'm working and close it into the nightstand when I'm in bed.  Just not seeing in your peripheral vision or feeling it in your pocket really cut down on a MASSIVE percentage of that passive, compulsive feeling to "check" something.  Even just 1 second of extra friction is enough to make a huge difference.
2. Set the phone UI to greyscale (black and white).  It is amazing how much less interesting / engaging this makes your phone even though it is still usable/functional its just not very enjoyable (which is what I want). 

Anyone else got any simple habits for reducing phone usage?  
 

 charge your phone in the room furthest from your bedroom.
if safety is a concern, there are other solutions (e.g. dumb phone, alarm). 

 I use a dumb phone as my daily driver but have a cheap smart phone without a sim card in it. I generally don't bring my smart phone out of the house with me, but I will if I envision needing it. I treat it like a mini computer and pull it out only when needed for some specific task. Doing this I get the best of both worlds in my opinion.