In my country, there are still a few Bitcoin ATMs around so I think it is best that it is improved first before having altcoin ATMs. In my opinion, there are plenty of things to consider in setting up an ATM machine not just because it is popular or its development is good. We should remember that crypto is very volatile that is why most investors are skeptical, not going all out, unlike before. Let's just wait for Bitcoin to be stable (in some way) first, I'm sure altcoins will come after.