On my folding bike, I kept them on because "they serve a purpose", but then realized that they were not allowing my wheels to turn freely no matter how they were adjusted.
Once I removed them, my wheels now spin forever. LOL
If they weren't causing trouble, I would have just left them on.
Edit: Ignore that I'm making it sound like there are two dork disks on my bike... it was on one wheel (rear) and only there was only one! LOL