This was honestly something I'd been wanting to get put together for a while...I just had to get past my recent deadline at work , lol. It is definitely going to be interesting to see how these go...especially compared to things already out there like Bitshares UIA's (User Issued Assets) and Ethereum's ERC-20 tokens.
On Steemit itself, I don't see it changing too much from what we're used to on here...mainly just the addition of the internal SMT market (which I'd figure would fit into the existing marketplace). I don't think we'll see any new upvote buttons or anything along with the current ones.
But...when communities are launched here on steemit (we'll actually have a 'create community' button to do this with) we might see spots where voting or other transactions would use their custom SMT. The big thing I foresee are communities actually moving off of Steemit itself to their own websites that have worked in the different parts of their SMT. The main thing people would then need Steemit for would be the wallet.
I have to look more into Bitshares, there seems to be a buzz about it and I was just lazy to check lol. That's one thing I like here though, I'm getting into concepts that wasn't readily available for me before Steemit. It's easier to grasp somehow because I'm part of it.
I like the concept of the create community button, I think it's the communities that keep Steemit moving and by giving these SMTs and autonomy to do what they need for their community would be powerful. It will take Steemit to a whole new level. Excited to see how it goes :)