Not to mention the person stealing your phone would have to know you and/or somehow have a nice close up, hi res picture of you.
While the likelihood is low, I was just stating that it was an known issue at one point. Plus, an Iris Scanner just gave me more reliability and confidence. To this day, my dad's S8+ has issues with facial recognition working spot on for a minute and then becoming erratic as Mark Sanchez the next minute. I had erratic facial recognition performance from the S8+ as well. Iris Scanner performed phenomenally if programmed correctly.