When creating my application's or library's configuration, I generally prefer using a custom configuration section over the <appSettings>
section for the following reasons.
Given this, when would I want to use the loose-typed <add/>
key/value mechanism of the <appSettings>
section? As I recall, application-level configuration in this section can override existing machine-level configuration from machine.config. Is this the only case, or are there other reasons?
It's easier for quick-and-dirty applications.
It's the same reason ASP.NET has things like the magic "Page_Load" method - no explicit wiring, you probably don't use it in an enterprise-y application; it's just there for RAD.