The point of this combo is speed. Sure, you can do it slower, but if you're running at a Lulu with R+E, she knows what's coming and gets ready to ult or polymorph. This version gives her no reaction window, it’s about bursting before they can respond.

Probably there are champions with combos with more inputs, and obviously smite would increase for anyone. People often say Master Yi has a low skill ceiling, but this combo shows there’s more depth than most expect, Yi’s kit has hidden layers if you put in the effort.

With Rageblade, Yi can apply on-hit effects 9 times in under a second using this 9-input sequence:
Stack Double Strike, then R + E + Flash + AA + W + AA + Smite + Q + AA.