It should be enabled for every node as the current SystemCleaner logic (up to 7.2.2) has certain steps specific to a given node (e.g., passivation data cleanup logic) along with other cluster/db level cleanups.
I don't think this is right for the reasons I mentioned in my earlier post - you will have passivation data not being cleaned up on a particular node. In general System Cleaner has some design limitation (up to 7.2.2) where too many things have been added to the same agent. That is why we separate to logic to stuff at node level and stuff at db/cluster level in future release (e.g., 7.3). What kind of performance issue are you referring? contention issue?