There are a couple ways to use these bots. Profit and exposure. You can only vote once on your own post they give the opportunity to have an extra vote from a decently high sp account for more money. These factors raise your visibility a lot.

If you are only interested in profiting from these type of botst then you are not getting the bigger picture. However if that is your only interest, this may help:

https://rawgit.com/msg768/mysteemit/master/bidder.html