Question to High elo adc players

hello i'm a plat1 adc, i never ever used attack move in my life, today i started trying some stuff and found that binding attack move click to left click it feels pretty good to me, but it fucks up everything else like moving on the map, some abilities and other stuff,.
i done my research and found out that every single pro adc player use attack move on A

can anyone explain me why? why do they use attack move insted of attack move click? its 1 more input so its way harder to use in my opinion.

and idk why but when i use attack move the auto feels slower than a normal right click or attack move click THANKS