"The bears might say that since anyone can create a side currency like this as often as they like, that pockets have no real worth, and just clog up the blockchain."

I fear that.  I'm already looking into a couple of meta-token ideas myself, and I'm sure others are doing it too.   The danger(?) is that people can effectively use the witnesses for free to transact their novel tokens.  Instead of building their own blockchain and doing all the hard work they can just attach it to the steem blockchain and take advantage of the work being done and paid for by others (with steem, not the novel token).