When we develop actions and specially change them later we sometimes remove code in the flow.
When a variable is not used anymore after changing / deleting some code in the flow service center warns you about this (yellow line under the variable and a message in the warning panel).
When an aggregate is not used anymore service center does not warn you about this.I would like service center to warn me so I can check if the aggregate can be deleted or not.
In the example below the GetUsers aggregate is not used.
Changed the category to Aggregates & Queries
Maybe it counts for advanced sql queries too but in there there might update, insert, delete statements which you want to happen. But it's a warning and the developer can hide the warning when he has validated it and it's still needed.
I wouldn't add it to adv. queries because it would possibly generate more false positives than actually scenarios where it would be useful.
Love the idea though! :)