What is the practical use for event groups?

I've been dabbling with the basics of Construct 2 for a month now. Some of the more advanced features that I initially ignored are now starting to interest me. One of these being event groups.

I can't seem to think of a situation where an event group would come in handy. All I know is that it can be activated or deactivated to enable a series of events at once. How does this differ with the use of sub-events?

First of all for cleaning your events and grouping everything.

I also use it for activating a series of events at once, can't really explain it, but its easier then subevents imo.