I’ve used a different pair and they do help when you are shooting in loose dirt where the smaller rubber feet have a tendency to sink in. I understand the reviewer found they worked well on concrete; the real question is how well do they work long term as aluminum feet will wear and will not stay sharp like they were when new. My prediction is a blunted/worn aluminum feet will grip significantly less well than the rubber feet. Another potential disadvantage of all of these wider spiked feet is they make the bipods more bulky up front and can snag more as you put the rifle though small opening like a Vickers barricade as we sometimes have to do in PRS matches.
Just something to think about. Basically not saying they are bad but that they work better and potentially worse in specific situations. I guess it's true for most things which is there are frequently no free lunches.