I agree with you that Twitter is a valuable way to help Steem... though I don't really agree that voting in straw polls is the way to do it
The best part of twitter IMO is the ability to think / converse with the larger blockchain community. There's so many smart people thinking out loud on that platform. In that sense, communicating and making new connections in this space is a GREAT way to build a personal platform. From that platform, it's easy to promote Steem (like I do - linking my Steem articles on Twitter, Facebook, etc)
My advice for non-tweeters looking to get started: Make an account, follow about 100 of the most interesting people you can find, and start putting aside a few minutes a day to read and tweet.