Thanks for your answer.
About item 1, I didn't know that you will always have a little profit from minnowbooster. I thought it works the same as all the bots with 2.4 hour bidding rounds. Which could result in a loss when there are to many bids in 1 bidding round.
About item 2, I Happen to have a different vision about this subject. I believe there are so many paid upvote bots, that it doesn't give any extra visibility. Simply because there are 1,000+ Steemonians that use this option on a daily basis.