Hm, mixed reviews eh? I am not sure about why these are only appropriate for track ends either, I have seen them on dropouts like mine (perhaps inappropriately).
FWIW my intended application was to (if possible) use this to help center the wheel up properly, as people say it does that. On my bike I find, perhaps because the dropouts are goofy, I'm not sure, the wheel always wants to angle to the drive side a bit whenever I am getting it reinstalled. I can usually work it back into place by moving the axel around but a simple solution would have been nice.