If you've ever heard an iPhone user talk about Do Not Disturb mode, it's essentially the same thing.
Blocking mode allows you to disable alerts for Calls, Notifications, Alarms, or the LED as a whole or on a schedule. If necessary, the setting also has an Allow List for contacts, in case you want select people to be able to reach you even when it's enabled. I use it on nights neither my wife nor I want to hear pings and dings throughout the night for email or app alerts. Not many realize the LED is connected to the light sensor in some way, getting brighter in darker environments.