Automation Rules are incredibly powerful but are limited to a very small subset of standard fields per item (ideas, epics, features, initiatives, etc.).
We're constantly finding ourselves wish that a standard field would exist so that we can create some amazing automations... below are a couple of use case examples.
Create an automation that assigns a 'to-do' if an epic has not been updated or commented on in the last two weeks
Create an automation that looks at a custom field for "T-shirt" and assigns a numerical value to the item scorecard for that item
Looking at several 'automation' ideas, most tend to boil down to enabling automation to have access to all standard fields for items.