Could you do a quick wind vs track computation with a slide rule? Slide rules built our country but E6Bs made flying much easier. When no one had invented a reasonable airborne computer our ancestors twisted up the mechanical computer we'd been using and added some stuff. I don't think I've ever piloted an airplane without one somewhere in my gear, it probably wouldn't actually do me any good these days, my fancy fingers and super focused brain have been left long in the past and I'd just wonder where the time went as I ran out of fuel and altitude a long way off course as I looked at a black LCD screen. Maybe not, you never know.