Until you can pay for food, rent, clothing, healthcare, etc etc with Dash, you can never close the loop.
While I totally applaud the effort, no one will use these vending machines with Dash. They may use the blockchain and Apple Pay or NFC, but never Dash. Why? 'Cos you have to buy Dash to spend Dash.
To be fair, the same goes for any currency, USD included... you gotta buy it (or be paid for your labor with it) to use it... so what?
USD is 100% premined, and instamined $2Trillion+/year by people who are not me...
I'd rather take my chances with crypto than fiat