Difference between 97% and 99.99% in perception is huge for autonomous driving purposes. 300x less likely to cause an accident.
Your Tesla might be 99.99% in recognizing red lights but will continue to drive straight into paper boxes in its immediate path.
odds of crash a => 97% => 3 / 100
odds of crash for b => 99.99% => 1 / 10000
improvement (odds ratio in this case) is then 300x = odds of crash for b / odds of crash for a