In a way, that’s unfortunate. On one hand, I have concerns about nodeinfo becoming required for federation when webfinger is already required. On the other, since “Application Actor” is not a well-defined concept, they and the extended nodeinfo support probably won’t become a general federation requirement and instead be an implementation-specific consideration.
I still believe we should have defined Application Actor better (requirements, behaviors, recommended practices) before, or in addition to, defining a discovery mechanism for a poorly-defined concept.