Check this hot take, Blizzard will never ban bots at any rate fast enough for them not to make their ROI. They buy more subscriptions/spend more than any normal player even someone like i that has 3 accounts. They get banned in waves which are weekly/biweekly(just a guess dont have an exact) why you ask? simple not cause they cant find whos botting with a /who followed by a gm messaged but cause they just resubscribe under a new fake email after each ban and they also offload their gold daily. Botting = permaban, buying/receiving gold from buying 2 week suspension.
On top of this they dont ban for trading items. so if its just a herb/mining bot the receiver account just sells it with no risk of ban. Im sure they found the appeal of x amount more subscribers vs selling a coin(wow token w.e u wanna call it) is more advantageous for when they sold to microsoft. Watch me get my post removed/suspended from forums.