Well bitcoin ATM machine is really a good idea because even without your exchange you can have access to your bitcoin via the machine and also its comfortablity in terms of buying and selling bitcoin will be much easier for users however there are a lot of risk associated with the ATM machine such as hacking of the machine which may leads to customers losing their money. So for me this calls for security concerns because they to have assured there customers of how safe or the measures they have put in place to safeguard their bitcoin while making use of the ATM machine. And also if the machine is making use of ATM card, is also another big risk because the card can be hack or when misplace which can leads to one losing all his bitcoin in a blink of an eye.
The Bitcoin ATM will also serve as the exchange, which eliminates the need for customers to exchange their coins to fiat first before using it to purchase whatever they want, but for the Bitcoin ATM to do that, they will definitely charge fees, which is common in every business. In terms of hacking the ATM and customers funds being affected, I think the ATM owners will be the ones at greater risk in such an incident because the hacker will target the system, and customers only go there to make use of the machine. I don't think their data will in any way be saved in the machine for the hacker to steal their funds from there.