In every good thing, there can always be pros and cons. Many of the upvoting bots are run by steemit witnesses for the purpose of helping minnows to gain attention for their articles if they don't have high steem power. Paying upvoting bot is explained to be like a marketing tool to get our article noticed. Nevertheless, I agree those who have more SBD can easily upvote themselves into trending. Little guys like me will need to be patient to get up there some day.