fe80::*
addresses are link-local in scope, which means the address is only valid for that particular network, the same address may reference a difference host on a different network. It is thus meaningless to specify a link-local address without specifying which network adapter. Also, DNS becomes rather meaningless outside of link-local scope such as provided by ZeroConf / multicast-DNS.
Unix hosts tend to specify the adapter by name, Windows hosts will specify the adapter by index. Note that Windows maintains separate interface indexes for IPv4 and IPv6.