It would be very useful to be able have an Action in an Automation that can trigger another automation.

This would be useful when:

Wanting to have 2+ automations have the exact same steps after a certain point. Instead of replicating those identical steps for every automation, you could separate them out and have the Action trigger that automation.

Simplifying complex automations down into smaller steps. This can be quite useful to keep larger automations from becoming cumbersome. Even more so, this can make it easier to troubleshoot large flow of automations and to turn off one automation subset for editing, instead of one whole thing.