Let $\Gamma$ be a discrete group and $A$ be a $C^*$-algebra. Consider an action $\alpha: \Gamma \to \operatorname{Aut}(A)$. There is a notion of amenability for such an action (see e.g. Brown and Ozawa's book "C*-algebras and finite-dimensional approximations", section 4.3), but how should one think intuitively about an amenable action? How was itthe definition originally motivated?