Many people complaining about the fee that occurred when they do transactions, and to be honest ATM is very good to increase the Bitcoin popularity but not many people want to used it, so I don't think it's very profitable to build a Bitcoin ATM machine
Exactly, the reasons why people using Bitcoin ATM machine are first they curious about it after they realize that the fee is too high they leave it or they don't have an option to buy Bitcoin with their cash or convert their bitcoin to fiat, while in most country there's already exchanger on each country, people can easily trade Bitcoin without going outside and lower fee of course, in my area there are two Bitcoin ATM machines as i can see it's not profitable moreover electricity cost is very expensive here.
To avoid that case, bitcoin ATM owners should apply normal fees such as what people always pay if they withdraw from exchanges.
No need to charge fee for buy bitcoin obviously as most exchanges regulate it that way, so it's convenient for customers.
The problem is whether many people will use this machine or not, and how much it costs to maintain bitcoin ATM per month to pay electricity or-and rent a place.