Whether it be the battery is dead or it just has not communicated/connected to HA in a certain amount of time I want to be aware and be able to easily check if all my devices are alive/functioning.
There are some automations for this but even those aren’t perfect. They utilize battery percentages which is not very accurate to begin with, and I have yet to see one that uses last seen or last updates to function properly.
Similar to errors and updates the dead devices should pop up on your settings screen at the top to make aware of it to resolve in a timely manner.