Not all the time. I ran into a situation where Microsoft expected such values to be there when later software was installed. You won't find this out until later. As it stands, deleting them now has now effect and they are "invalid" keys according to one set of rules. Microsoft's rules are from a rulebook we can't read so to determine if we toss or not is based on finding if it's some key Microsoft dropped in or not.
I started using this after it was recommended here. Most items that come up say, "File or Path does not exist."
Is is safe to delete all of these?