I think that more BTC ATM's could increase the adoption, due to the simple presence. If people see a BTC ATM they get automatically in contact with BTC. They don't have to buy BTC now, but they will wonder about what it is and do maybe some research and it's an easy way to buy BTC for beginners. Furthermore, it's similar to fiat ATM's and people are used to use fiat ATM's. The new, unusual thing "BTC" combined with something usual could decrease the fear of buying BTC which beginners often have.