They contain the same switches as the larger buttons, so the actuation force and all that is the same.
I did do some very quick experimenting one time using four of them in a Neo Geo layout. The idea was to have a tight grouping that would match how my fingers naturally rest without having to flatten my hand and spread my fingers out. It wasn't too bad for one and two button games, but on the four button games, it felt like using a keyboard.
In the end, I just couldn't get past the size. Small buttons just don't feel "arcade-y", even if they do use microswitches.
I could probably get used to them on a miniature or table-top build, but on a full size build I think they would always feel out of place.
Just my opinion.
