I can't say I ever made any good success from Twitter Ads the cost of them is crazy high. Organic has always proved to be better. Instead of paying twitter for ads ask the community to help. Write up a high quality article about how to get started on steemit, don't take any payment for it and ask the community to go retweet it. You will most likely have far better reach and would be good to do with any major updates done here on steemit/steem.

You legit have thousands of users eager to help and get Steem and steemit to grow start using that it is a free resource with massive potential.