Calling a shared feature intrinsic does not mean that the two activities are the same kind in every respect, or that their real essences collapse into one. Running and flying remain distinct activities, though traversal and speed create a common conceptual basis.
By contrast, the lion and the brave man can share the familiar characteristic of courage without that quality being part of the zoological definition of a lion. In this example, the connecting quality remains external to the defining concepts.
Ignoring this distinction would allow every feature to be labeled intrinsic or extrinsic arbitrarily. The classification is useful only when the actual meanings under analysis are stated.