It's a bitcoin vending machine. Owner of a bar/cafe/shop can accept bitcoins for payments and load them in this machine to convert them to cash. Those who want to spend bitcoins don't need to find those who want to buy them. Shops have easier way to accept and convert bitcoins into local currency => more places to spend bitcoins => more places where to buy bitcoins => more people using bitcoins => value grows => more…
The machine doesn't do BTC to cash, but rather the other way around.
When I said "owner can load BTC in machine to convert to cash", I meant that people from street will put in cash for his coins.