When this was posted it was rolled out for a subset of users. At this time it should be fully rolled out for all users.
That said, it's one full page scroll down, and that after two clicks at not-too-obvious menus. Not exactly in your face in terms of discoverability.
Hopefully this is just a first step – keeping archived sites indexed and/or automatically forwarding people to IA links once the original goes down would be amazing!
Within reason, of course; there's possibly a point where it would be a bit "too discoverable" and make people exclude their site from archiving as a general precaution. (I could see people being generally fine with being archived, but not with being google-able forever.)