I'm not pro bots or anything but I can see some advantages in bots

• they help new users grow rapidly, by upvoting their content (if your content is good, you will get on one of those upvote list
• the produce value for Steemit as a platform, growing the amount of Steem
  -they curate posts (this still has to be worked on, sometimes they vote shit)

Maybe there are other advantages and I'm sure there are disadvantages, but we will see how the platform is going to evolve