When in the parent task, and viewing the list of subtasks, there used to be a little speech-bubble icon to the right of each subtask that had a comment (or if it had sub-subtasks). I’m not making this up, right?
It was a helpful indicator that the subtask had “more info” in it, so you know to drill into it to.
I realize there’s still/now separate icons for if/when there are sub-subtasks or comments, but it’s also useful to know if and when there is simply a description in the subtask too. Now I find myself clicking into each subtask just to check if there’s more context.