Requested by out customer, to be able to trigger Automation actions following a group membership change.

For example:
A workflow may have an approval step, set to a Group attribute of an Assets object.

Any changes to the group membership should be reflected in the list of approvers in the Workflow's Approval step.

The solution suggested in the article, to update Approvers if an Asset object has changed, is not applicable for group membership update.

(the issue in the article was resolved later by implementing JSDSERVER-12730 - Approvers from Assets customfield should be updated when Object is replaced  in JSM 10.2.0)

Nor will other options to trigger if the same object has its Group attribute updates (can be achieved using a Webhook trigger from Assets' own automation) - as the Group attribute VALUE is not changed here...

So having an automation trigger for group membership updates can be useful to act and refresh the list of approvers already set on a ticket.