What about comment quality?

When I mentioned the follow4follow, I was referring to how those bots get their followers--those are impulse-based follows, generally providing little follow-up results. Concluding, the comment quality is likely very low.

Here's the thing: anyone can use these services due to their low cost barrier; so they can be easily flooded with weak content. So, if a few value-adding users manage to be those bots' audience, they'd soon unfollow after noticing that those bots do not curate.