Keith: They do give you the ability to enter email addresses; they just also provide the import tool as a convenience. I don’t really see it as giving my PIN to a stranger – I have used Facebook for long enough to trust them.
This feature turns what could be a long process (log into gmail, export your contacts, arrange them into the right format, import them into Facebook) into a very simple one. For me it’s worth the tradedoff. But it would be nice if there were a way to only grant them access to my addresses, and not my mail.