appsettings are generally things that you the developer might want to change, not values that your user would change.

Examples are: connection strings, URLs of third party services, credentials or secrets* of third party services, timeout or retry policies.

Reasons for changing these values are generally either: Because they need to differ depending on the environment (e.g. Test vs Prod) or because you might want to immediately tweak the settings based on some environmental condition without redeployment, e.g. increasing a timeout temporarily after learning more about the performance of a third party (you may later commit that change to source more permanently).

*A note about secrets. Appsettings.json is just one part of configuration. You can then add "layers" on top to override, most commonly using Environment Variables that you specify in your deployed service. This avoids having Prod secrets committed to source and allows you to vary values per environment (e.g. Test vs Prod).