Yep, it will be a "how could I have ever lived without this" feature. Currently, given the product's target market, the priority is to be able to import or otherwise access corporate/office directories (MS Exchange/AD or Google Contacts, or a directory accessed via a PBX).
The ability to download the phone's own, local address book via the standard Bluetooth profile is a planned feature that just wasn't working in time for the product's release. I assume it'll work sometime soon.
Incidentally, there appears to be a bug (not clear if it's firmware or hardware) that makes the OBiBT USB dongle malfunction when plugged into (if I remember correctly) the top USB slot. If you have weird issues with the OBiBT, try removing the dongle, deleting your phone off of the OBiTALK portal to clear out the existing BT configuration, and then plug the dongle into the other USB slot, and start over.