this question is not being answered in the game rules and i wanted to know if its allowed to use butterfly clicking with 4ms debounce time

It is allowed. But alot of the time it is done with a model O or modifing the mouse itself (VERY RISKY CAN BREAK YOUR MOUSE) I did it with my G502 light speed.

We do because I have stated so many time that I use it in my runs to the mods and there had never been a problem. It just allows people to click faster but still using human effort. Its not like installing a auto clicker on your mouse like some mice have.