If one was a coder once, they don't need to keep coding to understand what a coder does. Plus it's a bit hard to be a manager of different profiles and different stacks and understand what everyone does from a coding point of view (different stack, different frameworks and abstractions etc) especially while time passes and tech changes so much, so quickly.

I do agree that it's important for a coder to keep coding but mostly for the manager itself as it's removes some of the old biases and it's a continuous learning process on something that, technically speaking, they should be passionate about. Plus it does help to have conversations with other developers and don't sound like a person who only listens to vivaldi at a dnb concert.