I can't agree with you anymore if I'd written what you did myself. :)
I could understand the argument for advertising—if a bot actually put the post in front of more eyes. It doesn't really, though, not without a substantial bid. It could push it up the trending page a little in a lesser used tag, but that's about it. Someone would still have to scroll for it, again, unless it was substantial. Then you're hoping others are actually looking on the trending pages in the tags for content, which I do on a occasion, but that's not very often.
Beyond all of what you talked about, which believe me is bad enough, there's more: reputation skewing—for the user and the bot—value skewing—since people will think the post is worth a lot more than it will ever net—and curation hacking—since a lot of the bots are programmed to vote at the optimum time for curation rewards, the human curator will be locked out.
So, yeah. Bots create more problems than they solve as far as I'm concerned, which makes them a poor workaround.
Yes, as I mentioned there are many reasons I don't support vote selling, you covered a few more of them. I just focused on what I see as the biggest / most harmful to the platform.
I figured I'd just go ahead and mention them for the good of the order, but I agree, you hit the biggest issue. So, I'll ask this. How can we break the illusion that new users need to use the bots, so that they don't just hand over their rewards to the bot makers? Other than trying to educate people about bots, I've not heard any other solutions. Trying to convince a bot maker to stand down while they're profiting doesn't seem like a likely scenario. Is there something else that can be done?