bringing @arcturus in here for clarification, but as I see it, the card is 'ready' or it's not. Even if the API returns a null state (which means there's no card, or it is not-ready), we should return false (as we will be unable to import contacts) in that situation, and this check will return true.

For more information about the different cardStates, check https://hg.mozilla.org/mozilla-central/file/4919e8091542/dom/network/interfaces/nsIDOMMobileConnection.idl#l32 and comments on https://bugzilla.mozilla.org/show_bug.cgi?id=729173 (more updated than https://wiki.mozilla.org/WebAPI/WebMobileConnection)