Here are the basic central truths that we know about bots:
They don't care about content. The people that run them don't care about content. The operation and effective deployment of a bot is orthogonal to issues of content.
Very few people look at or care about the list of people/bots who have voted for a particular article. Implicitly, they care about content more than they care about the activity of the bots.
Bots are a fiscal sink. If they didn't make more for the people that run them than they pay out to the people that gamble in them, no one would run them.
So, we know they don't work for promotion because the only way that they can get content in front of our eyes is through Trending and Hot. Sane people don't look at Trending and Hot; the take away is obvious. We know they don't care about content, because they will upload anything equally as long as you pay them. Having removed the possibility of thinking about it as paying for advertising or as somehow validating your content, we are left with the only purpose for playing the bot game.
You want to make use of some of that pooled SP which would otherwise be motivated toward other content to instead be driven to vote for your content purely and only to increase the amount of funds you get out of the system.
Which I don't think is inherently bad, but it changes the nature of the platform. It's one thing to write what you like and what you're proud of and invite people to come see it and reward you if they like it.
Once you bring bots into it you have changed the nature of the platform from a blogging platform to a vanity press, a publication facility whom you give some money to in exchange for "distributing your book" and maybe getting more money back to you then you spent with the publication house to get the book printed.
At a smaller scale, that's exactly how the bots work.
It's exactly the same ripoff.
Sure, some people have made a fat wad of cash by going through the vanity press. And they are very sure to tell you about every single one of them whenever you wander by, just like the poker dealer at the casino shouting out how much people have won today as you walk by.
Steemit is a very different environment than the online traditional publication architecture. Thinking about bots as advertising does a disservice to advertising, and ad guys are not my favorite people on earth in the first place.