Where they are helpful is situations where a working might otherwise need to stand for hours on a hard (cement?) floor and they do make a difference, especially for hefty size workers. I put one in front of a table saw and another one for a chop saw where workers might be doing repetitive cuts for hours. One worker was over 220 lbs and had bad ankles, the mat helped him need fewer sit down breaks. Now I have one in my kitchen too, but it is prettier one. I can't say that the prettier one is better.
I think the benefits of these are overblown. They are most helpful when you do a lot of stepping on a hard surface; it cushions the repetitive blows to the joints. Just standing still, not very beneficial.
Probably not helpful on carpeting but poses a new tripping risk.