Difference Between Using `Effect.gen` and `Layer.succeed`

class Config extends Context.Tag("Config")<
  Config,
  {
    readonly getValues: () => Effect.Effect<{ value1: string; value2: string }, ValueGetError>;
  }
>() {}

const ConfigLive = Config.of({
  getValues: Effect.gen(function* () => {
  // Do Some Magic
  })
})

const ConfigLive = Layer.succeed(Config, {
  getValues: () => Effect.succeed({ value1: "value1", value2: "value2" }),
});