I have used these for years on all my hi-hat stands. These simply force hi-hat cymbals to return to their set position perfectly and quickly - not the case with the traditional felts which compress unevenly.
That's the benefit for me - for others they may offer another plus: a bit more "sizzle" from hi-hats due to less muffling effects than a felt that touches a larger area of the all-important cymbal bottom bell.
Anyway, highly recommended.