The danger is hitting your approach past the hole. Make this mistake and you’ll face one of the most challenging putts you can imagine. From the back-left to a front-right pin it’s a roller-coaster ride. Expect a lot of three-putts.
While it’s true that you need to pay attention to both the read and the speed neither one has to be perfect. You can make putts at any number of speeds as long as they’re reasonably matched to the appropriate line. The illustration at the top of the page proves why.
I think most golfers do about the same. Where some differ is in prioritizing the read over everything else. That’s where I emphasize the second-to-last step of the putting process: Matching the putt speed to the break.