The Angular documentation and Angular CLI push the Angular beginner (I'm in this boat) to implement application routing in a separate module from the main application, without really explaining why it gets this special treatment. For example, when I scaffold a new Angular project with routing using the CLI, I get a app-routing.module.ts file when is imported in my main app.module.ts file.
I have read the it's because of Separation of Concerns, but I have a hard time accepting this as the entire reason, because there are multiple concerns in an application, yet only routing is gets its own module.
As a beginner in Angular, I have no idea if this is an opinion based question, or there is a legitimate technical reason why it's a good idea. I can't find any information one way or the other, which is why I'm asking.
For those Angular veterens who have worked on medium-largish applications, when do you put or not put your application routing in a separte module, and why? Does it become technically necessary at a certain point, or is this simply a organizational convention?
Thanks.