Being up on the cards really doesn't mean anything, as with all legit quittages and stoppages, they are the best
outcome for the fighter.
Stopped against Lennox - Vitalis sight had deteriorated to the point where he would be unable to see punches, he could have gone blind, or taken too much punishment, either way, he certainly wouldn't have been up on the cards after 2 or 3 more rounds.
Quit against Byrd - had he fought on the injury would have been worse, given the pain he was in it's possible the ref may have stopped it anyway if he became unable to punch or defend himself properly. It was a little sad watching him trying to throw punches with his left during the 9th.
Byrd only had a week to prepare for the fight, imagine what a primed Byrd would have done