Show Cue System

It seems like auto start and sub cues accomplish the same things. Are there any guidelines as to when to use one or the other?

For example, I have two audio cues, the first is the sound of birds chirping and the second is a song.
The second cue starts 10 seconds after the first.

This can be accomplished using either using the cues as separate cues or having the second cue as a sub cue of the first.

This is a simple example, but I would like to know if there is way to determine which approach to use.

Thank you.

My usual determining factor for choosing either is if I want to see the autofollow cue in the cue panel. Sub cues, by default, don't display in the cue panel, while auto-follow cues do display. Choosing to marry a sound cue to another via sub cue means I don't see it in the cue panel. There has been a few times when I have made separate cues auto follow cues and, during a show, glanced at the panel to see a cue there with a number that isn't in my script (because I don't need to trigger it). This has the potential to cause confusion for an operator.
But there are times where I go into a production having created cues and later found it necessary to link some cues via auto follow rather than a manual start.