An R&A spokesperson gave an update on the situation stating, "We announced last year that we were reviewing green reading materials and expect to be able to give a further update in the coming weeks. We believe that the ability to read greens is an integral part of the skill of putting and remain concerned about the rapid development of increasingly detailed materials that players are using to help with reading greens during a round."
Green-reading materials are being used by just about professional golfer as well as amateur players nowadays. The amount of details on them is insane too. So I personally like the new rule as it will put pressure on players to actually use the skill of reading greens.
Jordan Spieth is also on board with the new change, as after his round yesterday stated, “I don’t think we’re allowed to use them starting next year, is that right? Which I think will be much better for me. I think that’s a skill that I have in green reading that’s advantageous versus the field, and so it will be nice. But while it’s there, certain putts, I certainly was using it and listening to it.”
However, there is also the notion that the detailed greens-reading materials were utilized to pick up the pace of play, as many player's might take too long analyzing their putt without the resources.
I can understand this point of view, but I still believe this skill has disappeared in the game as of late.
Governing bodies express that green-reading is a skill, and this new implementation will truly test this skill. It is planned to go into effect on January 1, 2019.