The other threads are likely refering to the 7100 not having Bluetooth sync or serial capability. RIM did not include this for security reasons.
The 7100 supports Headset and Handsfree profiles.
Back to the BT headsets themselves... not having a wire attached is worth 100 itself if your a phone power user. Convenience.
And BTW you can get into a top quality BT headset for way less than 100....
http://store.bizshopr.com/moths810.html
http://store.bizshopr.com/moths820.html
are two very popular examples that sound great on the 7100.
Check this thread too
http://www.blackberryforums.com/viewtopic.php?t=1016