Never gets old:

Might they think that there was a lot of cash inside since it was an ATM, but they thought that it was like a traditional ATM like in the bank.
Poor bandit didn't even think that the transaction of the ATM machines is all digitally linked to their wallet or their bank, not unless for those who are using paper bills on purchasing Bitcoin.
It's a BATM that does accept banknotes.
Besides, if the thieves had enough time they could have simply cashed out a lot of Bitcoin in multiple transactions once the BTAM was broken.
Insert $1000, buy coins, grab the money through the hole, feed the BATM again, and buy another 1k worth of
BTC or even more, you didn't even need the BATM to have any cash in it, you could use your own as you would get it back immediately.