Problem/Motivation
Starshot requires functionality that's not contained in Drupal core. The most prominent example is Sending notifications, e.g. when a new comment was posted, content was added or published, user signed up or logged in.
Another example may be to redirect users to the most appropriate site right after they've logged in, e.g. content editors to the content overview, administrators to the admin dashboard and all others to their profile page.
A lot more have already been or will be identified while Starshot gets fully defined over the next few months.
Proposed resolution
ECA and pre-configured models (provided as recipes) can do all of that - and of course much more. So, instead of adding extra modules for each of those extra requirements, Starshot should use ECA and the recipes, that are either already available or can be configured with very little effort, once their scope gets identified and defined.
This can be added without any UI, especially the BPMN.io interface, while being attractive to many, can be frightening to others.
For the purpose of the feature enhancement through ECA and recipes, there is no need for the UI component whatsoever. As soon as the user selects the recipes during installation, they will be processed as intended and there is no need to configure or change them.
For more advanced users, they can later enable the UI for ECA if they ever wish. But in the early days, they won't.