Hi Andrew,
Thank you for your question.
The main use cases for the D365/ACS connector are the following:
Synchronizing contacts from Dynamics 365 to Campaign so they can be targeted in marketing campaigns
Synchronizing custom entities from Dynamics 365 to Campaign so they can be used for segmentation and personalization
Sending email marketing events (sends, opens, clicks, bounces) from Campaign to Dynamics 365 to display in the timeline view
Synchronizing opt-out (e.g., do not email) statuses between Dynamics 365 and ACS to maintain customer privacy preferences.
To summarize, the connector was designed for data movement/synchronization; it was not designed to trigger events or actions within ACS. However, we'd love to hear more about your use case so we can understand it better.