I'd assume it makes you more consciously confident about pulling and hooking. But good players used to do that without the helmets anyway, and were liable to be struck and injured. Think Richie Benaud, Slasher Mackay, Bill Woodfull, Bert Oldfield. The instinctive fear of the ball wouldn't change much, whatever you were wearing, nor the ability to override that instinct and attack it.
It was pure idiocy from Lee, I remember discussing it at the time. The idea of having a windbag punter show up against a top-class athlete was fun for a moment, but Lee could have had his pride and a defensible position if he'd only targeted the stumps.
Six yorkers clean-bowling Morgan would have done the job with dignity. Instead Lee was bowling short three yards down leg side, from two yards in front of his crease. He showed his true colours that day.
Thanks for the comment AD, really appreciated reading your words there. It all happens so quickly.