In the ISO world, addresses are of varying format and length and just extracting the address from the packet may not be straightforward. Internet addresses can also refer to broadcast addresses. Of course, if the underlying network technology doesn't support broadcasting, one can't broadcast Internet datagrams either. Network addresses are written using dotted decimal notation. Each address consists of 4 bytes, and each byte is written in decimal form.
Internet addresses refer to network connections rather than hosts.
Gateways, for instance, have two or more network connections and each interface has its own IP address. Internet addresses are hierarchical addresses. Datagrams are initially routed only by network number, and only the gateway connected to the destination network uses the local part while performing the routing operation. Its Internet address must change. Now we get a better appreciation for why one wants to distinguish between a machine's name and its address.