WTH do i need a unique_id for?

I need a unique_id in my yaml to be able to edit the devices from the GUI (icon, etc.). With many years of histroy I have most in yaml.

Also, this unique_id field is not available for all types, thus I need to revert to customize and customize_glob yaml and REBOOT.

Implement this for everything, or create a solution per device / automation / scene / calc. sensor / etc. automatically not visible to the users.