STEEM could well become a currency in the traditional sense since it has a fast blockchain and zero transaction costs (at least directly to the one conducting it).
We shall see how that all evolves. I believe there will be hundreds of currencies used as money down the road...in fact, I can foresee multiple currencies in the same transaction.
I foresee STEEM becoming a currency in the traditional sense as it has everything needed by a transactional currency. Add to that a user base of several million and having a STEEM debit card might not be too far fetched. When atomic swaps become a reality any currency should be able to be used easily.
I agree with all that you wrote here.
A lot is possible depending upon the direction some people take it.
The great thing about the blockchain is that anyone with the know how can develop any of the things you discussed. It does not require permission or an agreement from a company.
If a programmer can create some of that stuff, like a debit card idea, then it is open season on that.