This is a valid argument, but how does one justify picking other coins that don't do anything yet?
I would actually vote for Maker and Dai before Steem. Those picks would synergize better with Coinbase. We absolutely need a decentralized stable-coin option. Adding Dai to Coinbase would allow businesses to accept Dai directly to a source that could be cashed out to an American bank account.
However, many of these nominations are clearly worse than Steem. Also, none of these coins are trying to do what Steem is attempting. Social media is pretty important.