When Blizzard changed their stance on Multiboxing they targeted some of the third party tools we were using. There have been many thousands banned for using AHK in very dumb ways. THis is a much longer post from a year ago - Guide: macros, WoW, you and more - #55 by TimothyLuke but the TLDR is using a third party tool is not safe. Its all about a measure of risk. at 250ms you don’t have an unfair advantage which you do over someone running at 50ms.
At a technical level all that stuff that Deexzyl has written is very real and a thing. if you run at 10ms you will DC yourself unless you are running a very powerful computer. Add to that running at 50 milliseconds your macro is just playing random whackamole so you have no control over what it is doing and no chance of making diagnosing what your macro is doing or why.
MODeration Note: I moved this to a new thread as it could disrail the original location.