Not for dwarf hamsters. I am not keen on Hamster Balls for Syrians for exercise either and prefer out of cage time on the sofa exploring or in a playpen area
But I do have a ball for our Syrian (savic rat ball) - and occasionally I do let him go in it but never for more than 5 or 10 minutes and being observed - then he gets a bit more sofa time. He seems to like it because he doesn't want to come out afterwards and keeps trying to run in it when it's still. But only once in a blue moon really, for a bit of variety. Mostly he prefers the sofa.
But they are risky and need supervision. Have also had a hamster escape from one! There are theories that hamsters are frightened in balls and trying to run away and also stories of toenails being caught and damaged in vent holes.
So it's just little and sensibly I think. A ball is very useful for transporting them (carrying the ball) from one room to another without them escaping and for letting them hop into when getting out of the cage for transporting them.
The main issues are. Standard hamster balls are too small for Syrians really, and not suitable for dwarf hamsters. Rat balls are a better size for syrians but have larger vent holes and so have different risks. The Savic Rat ball has the narrowest slits in but I'm careful to observe when our hammy is in it. But it also has knobbly sharp bits where it fastens which could hurt their feet (I filed them down).