I have never used a bot for anything. However for the most part their motive is to help themselves to the reward pool. As far as the “pay-for-vote” bots are concerned, you pay them $10 but only get rewarded $3. People just don’t understand that SBD are worth much more than $1, and what you get back is only 75% of the reward number you see. Generally a very poor deal.
I would love to see a blog on bots. I don’t know if you dare to write it. I would, but it’s neither my passion, nor my expertise. Unless you get into a whale war, bots aren’t interested in downvoting people as that eats into their time and money.