So personally I don't think it's that useful, it's almost equal to taking away power and then re-applying it.
The only difference is that RTC keeps running and can be used to wake the chip after a set time.
For example a magnetic reed switch sensor (door opening) or a PIR can be used to activate EN. The chip starts up and does whatever activation / notification is required.
In this scenario it is best combined with a diode feedback from a GPIO to keep EN high until the action is complete and to also use deep sleep to ensure the device returns to a quiescent low current state.
This method allows battery drain to be just a few microamps in its idle state.