That is not true. There are 827 ATMs listed on the site, but many of them only sell bitcoins. Far fewer of them will buy bitcoins and give you cash. The reason is that when the ATM owner buys coins from you he assumes the risk that the transaction will not be confirmed and he will be out the money. When the ATM owner takes your money and gives you bitcoins you are the only one taking a risk. I glanced at their list of ATMs near me and looks like 1 in 4 or less will buy your bitcoins.
The other thing about selling your coins at an "ATM" is that it isn't going to be a 1 minute process. When you sell coins, the ATM owner is assuming some risk that you will not double spend them and/or that they are legitimately yours. This means that you will have to wait for confirmation of the transfer. The confirmation of the transfer is the inclusion of your transaction in a confirmed block on the blockchain. Blocks are confirmed at approximately 10 minute intervals, so you are likely to have to wait at least 10 minutes and that is only for a single confirmation block. For any significant amounts of money, the recommended length of confirmed blocks for a transaction is 6. This means that it may take up to an hour before you actually get the cash! Don't plan on doing this on the way to the airport.