Features related to task / calendar / reminder behavior would ideally roam. For example if I mark a timed task completed on my Mac, it does not remove it from the calendar because that option was not checked (but it is checked on my Mac). So I think it makes sense to consider some settings as “global” vs “local” to that device.
However, I might suggest making them all global. Like I may want the same colors for the backgrounds on my devices.