Understanding Nested Effects in `Effect.cached` and Proper Usage

It's my first time using

Effect.cached

Effect.cached

and I'm wondering why it returns a nested effect? I've done some testing and it looks like immediately piping it into

Effect.flatten

Effect.flatten

doesn't break anything... am I using it incorrectly or misunderstanding how it's supposed to work?

Understanding Nested Effects in `Effect.cached` and Proper Usage - Effect Community