Sona in URF and why heal embargo did nothing to her winrate

DISCLAIMER - I am not complaining about Sona being op in URF, I actually main her, I am just explaining why she is so good in URF

There are other healers in the game, Soraka/Taric/Nidalee/Ali/Kayle/Nami who dont even get close to Sona's 70% winrate in urf, but why? her heal pales in comparison to some of these champions

Well what if I told you heals are not what makes Sona crazy overpowered in urf, but a characteristic what is quite unique in this game and also shared by some champions in the top 5 winrate of urf and HECARIM

She can cast while moving and not just one spell, all 3 of her basic spells This is what makes her OP

in 20 minutes she flies around lasering everyone on sight with her Q then oneshotting non tanks with her passive as well as spamming her heal and speedboost at the same time oh and she does this at like 550-700 movespeed