They do their job. Protects your cymbals from the screws.
Over time they do tend to stay in the form they're molded into when they have been on a cymbal stand the entire time (months) but it does not affect their use.
They do wear out after a long period and if you re-assemble your stands every week they probably deteriorate quicker.
But be honest, at this price? It's a no-brainer.