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.
The driver here is the merchant, not the customer. The customer can simply use apple pay attached to a credit card because they don't see a cost associated with that. The Merchant on the other hand, sees 3-5% bank fees, chargebacks, disputes, delays in getting funds from the bank. DASH solves those problems for the Merchant.