Hi
We normally use loopback interface which is again a logical interface for having IGP neighborship with the remote peers.
since it will remain up always regradless of your physical line connectivity.by that we do maintain the neighborship up and running.
i have seen some scenarios where we do use loopback interface for some kinda natting purpose like to have overloading on the loopback interface instead of the physical wan link interface.
as you have mentioned in ur first line thats pointing the static towards a ethernet interface its always better to have ip prefix of the next hop attached to that statement.
but i dont c attaching a policy map to a loopback interface since it doesnt forward any traffic or no traffic traversal happens thru that interface.
regds
