One of my concerns would be the possibility of misidentification that is then difficult to detect or undo. I think around 100,000 passengers per day travel through Heathrow Airport, so, if we had an accuracy of 99% in that context, we'd be talking about 100 misidentifications per day, which soon adds up. It just doesn't seem sustainable to me.
On April 4th, 2022. See this statement in context.