The way they work is you connect them to an exchange, add a markup. Any cash deposited you transfer back to the exchange and the difference is yours to keep. Rinse and repeat. The ATM pictured is a GB BATMTwo https://www.generalbytes.com/batmtwo/ and will also to allow you to sell up to two other coins (Ethereum is hot right now!) in addition to Bitcoin. There is standard support for BTC, LTC, ETH, Dash, Doge, XMR and more. If someone here knows who from the devs to contact at steemit to add steemit vending support to the ATMs. I can then point them to the Github API here: https://github.com/GENERALBYTESCOM/ as I think it could mean a massive boost for steemit ecosystem to have ATM support and should not be to hard to implement either.