Theres not enough macro space to play Ninja.

[Exstal]

theres no time to think about spamming which button if its on all the buttons

What's there to think about? It's one button.

its not one button if youre working on a rotation. besides that you wouldn't have to eyeball the targets hp for the execute range

Basically, you're incredibly lazy and you willingly make your gameplay suffer just to cope with your laziness. It has nothing to do with the amount of macro space.