How come non creatable/destroyable Roblox instances have :Destroy() :Clone() etc?

Roblox has many types of instances. But services and other NonCreatable Instances (ReplicatedStorage, Workspace, etc.) still have methods for creating or destroying. Why? Why do they have :Destroy() and :Clone() methods if they cannot be destroyed or created? What’s the point of inheriting these from the Instance class?