You are right. A few months ago Jawbone UP3 definitely had HRV listed in the heart health features. That's specifically why I was looking to buy it. I guess that's close to impossible with an optical sensor.
[1] http://www.dcrainmaker.com/2014/05/scosche-antbluetooth-opti... about 10% down the page [2] http://www.dcrainmaker.com/2014/05/scosche-antbluetooth-opti...