I believe that bid-bots are good bots which you
Can use to make a post become more popular
Bid-bots can make you get alot of upvotes on your post and the more upvotes you received
The more your chances of making your posts to
Become visible

Bidbots are also good as for promoting a new
Products and services,some people have used
Bid-bots to get their contents promoted on steemit and it worked for some people while 
Some other people claimed it did not work for them but whichever way you use them i must
Say bidbots are very useful though some spammers use it to spam on steemit

But the most important thing is that you should
Use the bidbots for a quality posts because when
You do that it will enable you to be able to get effective results from the bots which could lead to alot of upvotes on your contents and also more money

It all depends on the "quality of the post being upvoted" and the "amount" you have sent to the bidbot.

The "main" purpose of bidbots is to increase visibility of a post. If you are only sending 1SBD then for sure it will not even reach the "hot" section and no one will be able to see the post let alone have a chance of being upvoted by others. Most likely it will be drowned along with other posts after 5mins of being upvoted by the bot.

The next thing is "quality of the post", if your post is good enough then the moment it reaches the "Trending" or "Hot" section , chances are more people will see your post and will likely upvote it. The downside of course is if your post is of low-quality then instead of being upvoted, you'll be downvoted.

More visiblity = More chances of being upvoted = More profitable