[senux]

Just to complement other's responses, accessibility is a spectrum.

We ought to believe someone chooses to use an icon for aesthetics AND usability reasons. If the icon can't be rendered at all, it defeats it's purpose despite it having a "description".

Ultimately, if a well designed, user-friendly system doesn't work the way it's intended to, it is an accessibility issue of some degree. Albeit, some times more trivial than others.