There are more advantages to do this then not.
The states that need to be unkown at reboot could be set to that state when ha is starting . This is what I do with HomeSeer "device/features ".
Now, Every automation involving a timeframe wont work if there is restart of the system. The solution of keeping the state while rebooting is far aimpler that all the methods needed to work around a state set to unknow at restart.