Quick question: If the ownerDocument is to return null if it is a document or document if it is another node type, why does the number 4 of insert a character says the following:

Otherwise, create a new Text node whose data is data and whose node document is the same as that of the element in which the adjusted insertion location finds itself, and insert the newly created node at the adjusted insertion location.

I am referring to the bolded part above, why do I need to use the document of the adjusted location in the Text node yet again if each node has an associated node document set upon creation, wouldn't that be superfluous since they likely point to the same document anyway?