What's the difference between "Icon override" in entity settings and the "Icon" attribute in Customizations?

I am fiddling with device classes and icons and I don’t get the difference between setting the “Icon override” in the properties of the entity itself and using the Customizations feature where I can also override the “Icon” attribute (even it’s not proposed by default).

I find it a bit inconsistent / counterintuitive because when I set it at some place, it does not appear at the other, so I understand there is some kind of “overriding cascade”. From my testing, the Customizations will override everything, even the “local entity” override.

Icon override (when you click on an entity and click on the settings)
image

Icon attribute in Customizations

I know this specific example does not make sense and I just need to use Customizations to update the device classes but that’s not the point here. Maybe that’s the same thing for the Name override. I did not test.