wonder how do they plan to achieve this from the technical standpoint
ATM where you can both buy bitcoins and easily cash out bitcoins without the need to use third party processors
It's not that difficult to be honest. It only requires a software/firmware upgrade and that's it. You use your card to purchase whatever amount of Bitcoin that the machine allows you to (legally) purchase, and you'll get a receipt with a private key printed on it. Considering that when you purchase Bitcoin with your card they technically have all your personal information already, it saves people a ton of verification hassle as well.
The article title however is very click-bait oriented. I think that in reality if we can see 10% of that figure deployed, it's a major achievement already. You can't just turn every ATM into a BATM, especially not when you take into consideration that each state has different policies you have to abide by.
In the end, more BATM's means more average joe level of accessibility, which is a good thing.