I think for the next year to two years, backend development on ARM Mac will come with some additional pain. There will always be some package with a C extension that doesn't compile on your platform (for example).

As a non-Mac user (and someone who develops for ARM targets of all sizes) I'm really happy about the situation though. Apple is forcing developers to not be able to assume processor architecture any more, just because what they're developing is aimed at desktop. Lots of software is going to become more portable and we'll all benefit. In the meantime though, I'm going to keep developing on x86/64.