Thing is, when they DID eliminate them all, I noticed a marked increase in the performance of the game. Now as they come back thick and fast, it really makes me believe they are the stimulus to much of the lag in the game.
Not only that, but newer players simply cannot gain materials for crafting - and so we see lots of players not continuing to play, and those that do just immediately make a passive decision to not do any of their own crafting.
Follow the gold trail.... watch how these bots give to a single account, then sell the items to well known traders (some of whom I know, and they are/have been GMs of some of the bigger Trade Guilds too)... then that gold gets sold on websites to players (against TOS).
It all ends up hurting ZoS in the long run... because it effects performance, but it also means the crown sellers/gifters are doing far less business, and that hits Zenimax in THEIR economical pockets too.