Forgive me but I fail to see how this promotes the mass adoption of cryptocurrencies.
What Zeex does, if I understand it correctly, is help you convert your coins into a gift card,
which you can then use to buy coffee. It's more or less the same as converting your coins into fiat money
in order to buy coffee. If Starbucks really wanted to help promoting crypto, it could accept direct payments in crypto.
Earlier this years one of the Starbucks' CEOs said that he didn't believe in Bitcoin.
That's enough of a hint to me as to what their position is.
So your point would be not to use crypto at all? This is a solution for not having to convert back to fiat and not having to pay fees.
So as a personal example as a UK crypto holder I would have to convert my eth back to fiat using Coinbase with the fees and time it entails and then wait for it to clear in my bank account before buying my coffee at Starbucks.
Or I could do as the guy in the video did, walk into Starbucks buy a gift token with eth or zix using the app and be out there in minutes with my coffee.

I don't see this as the be all and end all of mass adoption but it is a step in the right direction.