voting bots that are making profit aren't really necessary.
Services like minnowbooster and steemfollower are pretty much necessary for minnows to see any growth on Steem, unless you are unemployed and have all day to promote yourself through commenting and spamming. In fact, I would argue that if Steem worked more like steemfollower where you get points for upvoting others that in turn get your posts more visibility, for-profit voting bots would be a joke.