Is it legal to install ATMs for the purchase of cryptocurrencies?
This may contribute to money laundering or other financial fraud.
It depends on which country you want to install ATMs. In the US, a lot of Bitcoin ATMs and they all work legally. You can run into problems in China or Russia
In the USA, it is not possible to install ATMs in all states.
I think that in any country problems may arise if the entrepreneur does not receive a license for currency exchange.
However, in the United States most of all Bitcoin ATMs. A very large number of Americans invest in Bitcoin and believe in cryptocurrency