I must admit that I have used bots a few times, especially when I'd just joined the platform. I saw it as a chance to get some exposure, but truth be told, it simply led to a negative ROI.
I understand why people use them, just as you've outlined above. However, I am now of the opinion that they're detrimental to the platform. Potential top quality content is being washed away in favour of content that has been paid to sit at the top of the trending list. There is no quality control. If you pay the price, you get the upvote.
It seems to me that these bots simply allow the rich to get richer, while the reward pool isn't being shared on merit.
I understand the desire to take advantage of such a service, especially when you're new. The RoI is a curiosity, too. I have a feeling that it ends up not being as profitable as it seems.