Alcoholics will tell you they slept great.
Sleep is what, the polar opposite of conscious activity ? That sort of negates the concept of "doing something" to get better sleep.
The best sleep you are ever going to get is to lay down in quiet room with no light, noise, or other distractions, including mental ones, and simply do nothing.
Where you find that quiet room ... I have no idea.
Joking aside, I use federal/state legal hemp at times to achieve hyperfocus. A substance that provides hyperfocus is not something I would reach for to provide better sleep.
They are missing an important variable and all results should be taken with necessary salt dosages.
People that don't use it, but have tried it, tell me it "puts them to sleep."
For myself, it wakes me up.
I think it all depends on the users baseline biology as well as the strain, so blanket statements like the study headline seem difficult to actually test for.
sativa is the strain for heading deep thoughts
(ime, ymmv)