There are lots of bots here. @robotev (and related) is a curation bot. I expect it follows what I vote on in an effort to help good content. You can click on the voters to see if they are people or not.
I'm interested to see if it can scale. There is a certain amount of Steem available each day for curation and post rewards. If people decide Steem has a value then the price will go up and people will still potentially earn a nice amount. I personally think that some of the earnings in the past were over the top with some posts making $000s. The crash of the price from $4 to cents may mean others thought the same.
Bitcoin is no different to Steem and that has a market cap of billions, so someone thinks it's viable. You can find plenty of discussions on what constitutes a currency around here. Most of it is beyond me.