Well said, Fredrik!
I have come to realize this as well, by noticing that most of the successful users whose content I enjoy (like you, of course!) never use this kind of service themselves. I tried using booster a handful of times, but found that it really doesn't make a difference. Also, by reading more abut how bought votes can negatively impact the platform (the evidence is there that at least it's not improving the quality of the content posted) I was finally convinced to stop using them altogether.
I must say that I was really taken by surprise to see the number and size of upvotes on this post. I've written many that have taken me a lot longer to write that received only 1/5th, or less, of the expected rewards. But if I have learned one thing from observing successful bloggers, then it is the fact that it is not just quality of content that gains traction and make people want to support you. It is just as much (if not more) based on whether you through transparency and storytelling come across as someone people would like to help succeed, or like to follow on one's journey.
I have a similar experience, some posts that I really put a lot of work into don't give me anywhere as much ROI as I hoped, however I have been surprised by articles that I thought were just OK suddenly skyrocketing and getting lots of rewards and engagement. I guess the key is to stay consistent and just put our work out there, let the audience be the judge!