Firstly, I prefer manual curation. To answer your question, I personally feel that Minnowbooster gives people who use it some hope that they can get noticed on the hot pages and a little reward for their curators as a thank you. When people put their heart into their work, and it gets lost on the sea floor, it's a means to feel positive for the reasons above. As you have significant SP, I can understand that it might not be something you've personally experienced.
Minnowbooster is also very transparent service that's a predictable option over others that are either random, or have some form of chance to them. You can confirm via minnowbooster.net.
I'm not huge on bots, but in my limited experience so far, I feel the best about this one if I've elected to use any. On top of that, @reggaemuffin is one of the best Steemians out there behind much of the back end of it, and I know that they care immensely about its vision.
While investors can passively delegate heavily to it for ROI on minnow payments, I believe that the vision behind what it's there for in the first place is true to how I've interpreted it.
I chose to earn my SP from nearly scratch, so I suppose I'm biased from a minnow's view at this time. I could flip a few BTC and change this experience for an easier street, but I want to learn from the ground up to relate to everyone.
Thanks for catching my comment. I'd appreciate any of your personal views or further discussion as I have much to learn, but also much to share.