Simpson wrote about those, I think. And Hurdzan basically said the same thing in his book.
In Simpson's day, they were considered sporty, but over time, I suspect one too many greens chairman came up short and felt it was unfair that his ball rolled back from the front of the green. Then, they were gone, in the name of fairness, speed of play, receptivity, etc.
From the supers point of view, a mound just inside the front of the green may require more watering. However, the heavy traffic and mower turning just in front of the green means that any overwatering to accomodate the green may make that area too wet, leaving mower tracks, etc. not to mention taking away any run up option, as if anyone uses it.
Somewhere along the line, all of those factors doomed this quirky little feature at most clubs......Just my opinion, based on my experience......If I used it at all, I would use it just once or twice per course. Jay Morrish used that feature about once per course for a period of time. In some ways, I think it is a historical nod to the 4th at TOC.....