I have a greyscale desktop setup (ex-Xray review monitor) that I occasionally fire up and use for writing. Not sure how to describe it other than 'calming' in the sense the lack of color is one less distraction. I picked up the greyscale 'habit' back when mono VGA monitors were much cheaper than color and I picked one up being short of cash. Later, the beautiful NeXT mono setups sold me.
I have been using greyscale mode on my Android phone for number of years (starting when it was only available through dev console). It is very interesting cognitive experience. I learned very quickly that colors drive a lot of context that I usually don't pay attention to. I wouldn't say that I have been using phone less, because of the greyscale mode. Give it a try, maybe you will like it.
Set it up recently at the suggestion of a friend and it definitely makes things jump out less. If anything my macbook feels way brighter as a result. Curious if it also helps me reduce my iphone usage!