The part about separating blockchain and currency is a very important topic that gets brought up a lot from skeptics, so I'm glad you touched upon it. I completely agree that there is no separation of the two. The tokens are the incentive for participating in consensus, simple as that.
But I wonder... With no direct incentives for participating in consensus, is there a case where entities would participate "for free"? In fact there are such proposals where all participants, not necessarily just miners, contribute to consensus (iota comes to mind here). If you take iota and changed its data to not store balances and transactions, but instead changed it to storing game state and game actions, you have a decentralized game without a central token. Hmmm.... Food for thought.... Even in this example though there's a hidden incentive mechanism (being able to play), so I think it still counts and doesn't detract from all the excitement.